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freeman500:
What model and brand?

.
Toyota Corolla 2006 sports

Please who can read this code very well for acura mdx.

P0685.

Mechanics electrician is saying the brain box is dying.

lordfalcao:
Please who can read this code very well for acura mdx.

P0685.

Mechanics electrician is saying the brain box is dying.

Good afternoon sir.

Vehicle: Acura MDX
Fault Code: P0685
Concern: Your mechanic/electrician suspects that the engine computer (ECU/PCM) is failing.

Before concluding that the brain box is dying, I would recommend a proper electrical diagnosis. P0685 does not automatically mean the ECU/PCM is faulty.


1, What P0685 Means

P0685 — ECM/PCM Power Relay Control Circuit/Open

In simple terms, this code indicates a problem involving the engine computer’s power-relay control circuit. Depending on the Acura MDX model year and system configuration, the fault may involve the PCM power relay, its control circuit, wiring or power supply.

Possible causes include:

• A faulty PCM/ECM power relay.
• A blown fuse or poor electrical connection.
• Loose, corroded or damaged wiring.
• A poor battery connection or grounding issue.
• A fault in the relay-control circuit.
• In some cases, an internal PCM/ECM fault.


2, Does This Mean the Brain Box Is Dying?

Not necessarily, sir.

Although an internal PCM fault is possible, it should be considered only after the external power supply, relay, wiring and control circuits have been tested.

Replacing the brain box prematurely could result in unnecessary expenses. Depending on the vehicle, a replacement PCM may also require programming, immobilizer pairing or other configuration procedures.


3, What Symptoms Should You Look Out For?

Depending on the underlying fault, you may experience:

• The engine refusing to start.
• Intermittent starting problems.
• The engine cranking without starting.
• The engine computer failing to communicate with a diagnostic scanner.
• Unexpected engine stalling or loss of power.
• The fault returning after being cleared.

These symptoms are not exclusive to P0685, so the actual behaviour of your MDX is important to the diagnosis.



4, What Should Be Checked Before Replacing the Brain Box?

I recommend the following checks:

1, Battery and Main Power Supply: Test battery condition, terminal connections and relevant power supplies.

2, Fuses and PCM Power Relay: Inspect the relevant fuses and test the relay’s power contacts and operation under the manufacturer’s specified conditions.

3, Wiring and Ground Connections: Check for loose connections, corrosion, damaged wiring and excessive voltage drop.

4, Relay Control Circuit: Verify whether the relay is receiving the correct control signal and whether the circuit is open or shorted.

5, Computer Communication: Use a suitable diagnostic scanner to check PCM communication and retrieve all related fault codes.

6, PCM Assessment: Only after the external circuits have been verified should an internal computer fault be seriously considered.


5, Do NOT Do This

• Do not condemn the brain box based on P0685 alone.
• Do not keep replacing relays or fuses without identifying why the fault occurs.
• Do not bypass the PCM power relay as a permanent solution.
• Do not install a replacement computer without confirming compatibility and programming requirements.

The aim is to identify the actual cause before spending money on an expensive component.


• Professional Insight

P0685 points us toward the PCM power-relay control circuit, but it does not by itself prove that the computer is failing.

A faulty relay, damaged wiring, poor electrical supply or grounding problem can produce a similar fault. Proper circuit testing is necessary to distinguish these possibilities from an internal PCM failure.


• Ryan Automotive Limited Recommendation

At Ryan Automotive Limited, we recommend a structured electrical diagnosis before condemning or replacing the brain box.

Our assessment would focus on the PCM power supply, relay operation, wiring integrity, grounding, diagnostic communication and related fault codes.

• Kindly provide the following details so we can guide you more accurately:

* Acura MDX year of manufacture.
* Engine size, if known.
* Whether the vehicle starts, cranks without starting, stalls or refuses to crank.
* Whether P0685 is the only fault code or other codes are present.

If you are in Lagos or can bring the vehicle down, you are welcome to visit Ryan Automotive Limited, along LASU–Isheri Road, for a professional assessment.

We diagnose the fault first and explain our findings before recommending repairs.

RYAN AUTOMOTIVE LIMITED
Precision • Transparency • Excellence.

I notice two issues with my car, 1. The rpm needle usually spike suddenly and returns with a vroom sound while driving, sometimes i feel a jerk like galope on a smooth road. I noticed increase in fuel consumption.
Secondly sometimes in the morning even when i allow the engine to warm, if i engage drive engine revs but barely move accordingly, i have to switch between park and drive again before it moves normal.
What could be the possible problem.
Model; Camry 2008 2gr engine.

Frankspot:
I notice two issues with my car, 1. The rpm needle usually spike suddenly and returns with a vroom sound while driving, sometimes i feel a jerk like galope on a smooth road. I noticed increase in fuel consumption.
Secondly sometimes in the morning even when i allow the engine to warm, if i engage drive engine revs but barely move accordingly, i have to switch between park and drive again before it moves normal.
What could be the possible problem.
Model; Camry 2008 2gr engine.

Good evening sir.

Vehicle Details
Make: Toyota
Model: Camry
Year: 2008
Engine: 2GR V6

Complaints:

1. RPM needle suddenly rises and drops while driving, accompanied by a vroom sound, occasional jerking and increased fuel consumption.
2. In the morning, when Drive is engaged, the engine revs but the vehicle barely moves until you shift back to Park and engage Drive again.

These two symptoms may be related, but we should investigate them systematically before condemning the engine or transmission.


1. RPM Suddenly Spikes While Driving

You mentioned that the RPM rises suddenly with a vroom sound and then returns, sometimes accompanied by a jerking sensation even on a smooth road.

One important possibility is transmission slipping or an abnormal gear change, particularly if the engine RPM rises but the vehicle speed does not increase proportionately.

Other possible causes include:

• Transmission fluid level or condition problems.
• Hydraulic pressure loss within the transmission.
• A faulty shift solenoid or valve body issue.
• Torque converter or internal clutch wear.
• An engine performance problem involving the throttle body, air-metering system, ignition or fuel delivery.

The increased fuel consumption may be related to the engine revving excessively or the transmission not transferring power efficiently. However, we need to establish whether the RPM spike is caused by the transmission or the engine itself.


2. Delayed Movement When Selecting Drive in the Morning

This symptom deserves particular attention.

You explained that even after allowing the engine to warm up, you engage Drive, the engine revs, but the vehicle barely moves. You then shift back to Park and select Drive again, after which the vehicle moves normally.

This may indicate delayed transmission engagement, where the transmission does not establish sufficient forward drive immediately when Drive is selected.

Possible causes include:

• Low transmission fluid or fluid loss through a leak.
• Incorrect fluid level or unsuitable transmission fluid.
• Hydraulic pressure draining down while the vehicle is parked.
• A sticking valve body or malfunctioning shift solenoid.
• Internal seal leakage or wear affecting the forward clutch circuit.
• Internal transmission wear.

The fact that the problem improves after shifting out of Drive and selecting it again does not prove that the gearbox is damaged beyond repair. It does, however, warrant proper transmission testing.

3. Important Observation

The combination of RPM flare while driving and delayed Drive engagement in the morning makes the transmission a major area of concern.

If the engine revs higher without a corresponding increase in vehicle speed, transmission slipping becomes a stronger possibility.

However, if the RPM rises and falls while the vehicle’s speed changes normally, an engine-management issue or normal transmission downshifting may also need to be considered.

We must distinguish between these situations before deciding on the repair.


4. What Should Be Checked Now?

Before replacing any components, I recommend the following:

1. Transmission Fluid Inspection

* Check the fluid level using the correct Toyota procedure.
* Inspect the fluid condition and confirm that the specified ATF is being used.
* Check for leaks around the transmission, cooler lines and related connections.

2. Computerized Transmission Diagnostics

* Scan the engine and transmission control systems for current, pending and stored fault codes.
* Examine available transmission live data and relevant freeze-frame information.

3. Cold-Start Engagement Test

* Assess how long the transmission takes to engage Drive and Reverse after the vehicle has been parked overnight.
* Compare engagement behaviour when cold and when warm.
* Check whether Reverse also experiences a delay.

4. Road-Test Diagnosis

* Monitor engine RPM, vehicle speed and gear-command data where available.
* Determine whether the RPM flare occurs during a gear change or independently of shifting.

5. Hydraulic and Mechanical Assessment

* If initial checks indicate a transmission problem, carry out the appropriate hydraulic pressure tests and inspect the valve body, solenoids or internal clutch circuits as indicated by the findings.

6. Engine Performance Assessment

* If transmission testing does not explain the RPM fluctuations, investigate throttle operation, ignition, fuel delivery and relevant engine live data.



5. Do NOT Do This

• Do not keep revving the engine to force the vehicle to move when Drive engagement is delayed.

• Do not repeatedly shift between Park and Drive as a long-term workaround.

• Do not top up the transmission with an unspecified fluid or use additives without identifying the problem.

• Do not authorize a complete gearbox replacement based on symptoms alone.

• Do not ignore the RPM flare, jerking or increasing fuel consumption.

If the transmission is slipping, continued driving can generate excessive heat and worsen internal damage. If the vehicle struggles to move or loses drive unpredictably, have it inspected before further driving; towing may be the safer option.

⸻

6. Professional Insight

For your 2008 Toyota Camry with the 2GR V6 engine, the two most important diagnostic concerns are:

First: The sudden RPM flare while driving, especially if the vehicle does not accelerate in proportion to the increase in RPM.

Second: The delayed engagement of Drive after the vehicle has been parked overnight.

Together, these symptoms raise suspicion of a transmission engagement or pressure-related problem, although the actual cause cannot be confirmed without testing.

The next step is to establish the transmission fluid condition, retrieve any relevant fault codes and assess its behaviour during cold engagement and road testing.


7, Ryan Automotive Limited Recommendation

At Ryan Automotive Limited, we recommend a structured diagnosis before any major repair is authorized.

Our assessment can include:

• Computerized engine and transmission diagnostics.
• Transmission fluid and leak inspection.
• Cold-start engagement testing.
• Live-data monitoring and road-test assessment.
• Further hydraulic and mechanical testing where necessary.
• Identification of the root cause before recommending repairs.

If you are in Lagos or can bring the vehicle down, you are welcome to visit Ryan Automotive Limited, along LASU–Isheri Road, for a professional assessment.

We diagnose the fault first and explain our findings before recommending repairs. Our goal is to identify the root cause, not replace parts through guesswork.

• One important question: When the RPM suddenly spikes while driving, does the vehicle’s speed increase with it, or does the RPM rise while the car barely accelerates?

That distinction will help narrow down the likely cause.

RYAN AUTOMOTIVE LIMITED
Precision • Transparency • Excellence.

We are just clueless in possession

RyanAutomotive:
Good afternoon sir.

Vehicle: Acura MDX
Fault Code: P0685
Concern: Your mechanic/electrician suspects that the engine computer (ECU/PCM) is failing.

Before concluding that the brain box is dying, I would recommend a proper electrical diagnosis. P0685 does not automatically mean the ECU/PCM is faulty.


1, What P0685 Means

P0685 — ECM/PCM Power Relay Control Circuit/Open

In simple terms, this code indicates a problem involving the engine computer’s power-relay control circuit. Depending on the Acura MDX model year and system configuration, the fault may involve the PCM power relay, its control circuit, wiring or power supply.

Possible causes include:

• A faulty PCM/ECM power relay.
• A blown fuse or poor electrical connection.
• Loose, corroded or damaged wiring.
• A poor battery connection or grounding issue.
• A fault in the relay-control circuit.
• In some cases, an internal PCM/ECM fault.


2, Does This Mean the Brain Box Is Dying?

Not necessarily, sir.

Although an internal PCM fault is possible, it should be considered only after the external power supply, relay, wiring and control circuits have been tested.

Replacing the brain box prematurely could result in unnecessary expenses. Depending on the vehicle, a replacement PCM may also require programming, immobilizer pairing or other configuration procedures.


3, What Symptoms Should You Look Out For?

Depending on the underlying fault, you may experience:

• The engine refusing to start.
• Intermittent starting problems.
• The engine cranking without starting.
• The engine computer failing to communicate with a diagnostic scanner.
• Unexpected engine stalling or loss of power.
• The fault returning after being cleared.

These symptoms are not exclusive to P0685, so the actual behaviour of your MDX is important to the diagnosis.



4, What Should Be Checked Before Replacing the Brain Box?

I recommend the following checks:

1, Battery and Main Power Supply: Test battery condition, terminal connections and relevant power supplies.

2, Fuses and PCM Power Relay: Inspect the relevant fuses and test the relay’s power contacts and operation under the manufacturer’s specified conditions.

3, Wiring and Ground Connections: Check for loose connections, corrosion, damaged wiring and excessive voltage drop.

4, Relay Control Circuit: Verify whether the relay is receiving the correct control signal and whether the circuit is open or shorted.

5, Computer Communication: Use a suitable diagnostic scanner to check PCM communication and retrieve all related fault codes.

6, PCM Assessment: Only after the external circuits have been verified should an internal computer fault be seriously considered.


5, Do NOT Do This

• Do not condemn the brain box based on P0685 alone.
• Do not keep replacing relays or fuses without identifying why the fault occurs.
• Do not bypass the PCM power relay as a permanent solution.
• Do not install a replacement computer without confirming compatibility and programming requirements.

The aim is to identify the actual cause before spending money on an expensive component.


• Professional Insight

P0685 points us toward the PCM power-relay control circuit, but it does not by itself prove that the computer is failing.

A faulty relay, damaged wiring, poor electrical supply or grounding problem can produce a similar fault. Proper circuit testing is necessary to distinguish these possibilities from an internal PCM failure.


• Ryan Automotive Limited Recommendation

At Ryan Automotive Limited, we recommend a structured electrical diagnosis before condemning or replacing the brain box.

Our assessment would focus on the PCM power supply, relay operation, wiring integrity, grounding, diagnostic communication and related fault codes.

• Kindly provide the following details so we can guide you more accurately:

* Acura MDX year of manufacture.
* Engine size, if known.
* Whether the vehicle starts, cranks without starting, stalls or refuses to crank.
* Whether P0685 is the only fault code or other codes are present.

If you are in Lagos or can bring the vehicle down, you are welcome to visit Ryan Automotive Limited, along LASU–Isheri Road, for a professional assessment.

We diagnose the fault first and explain our findings before recommending repairs.

RYAN AUTOMOTIVE LIMITED
Precision • Transparency • Excellence.

thank you.

The model is acura mdx 2010
Engine size is 3.7l

The vehicle jerks while trying to go from 0-40 kmh when driven for quite a time.

The other code shown is p2649

lordfalcao:
thank you.

The model is acura mdx 2010
Engine size is 3.7l

The vehicle jerks while trying to go from 0-40 kmh when driven for quite a time.

The other code shown is p2649

Good evening sir.

Thank you for providing the additional details.

Vehicle: 2010 Acura MDX
Engine: 3.7L V6
Fault Codes: P0685 and P2649
Complaint: Vehicle jerks during acceleration from 0–40 km/h after being driven for some time.

Based on these details, I would recommend investigating both fault codes before concluding that the brain box (PCM) is failing.

1. Understanding the Two Fault Codes

P0685 — PCM Power Control Circuit/Internal Circuit Malfunction

On this particular Acura MDX, this code relates to the PCM power-control circuit and its shutdown process. It can be associated with an internal PCM problem, but the manufacturer’s diagnostic procedure also requires checking for intermittent electrical faults and loose terminals at the PCM power-supply connections before replacing the computer.

P2649 — Rocker Arm Oil Control Solenoid Circuit High Voltage

This code relates to the VTEC/rocker-arm oil control solenoid circuit. It indicates that the PCM has detected an abnormal electrical signal in that circuit.

Possible causes include:
• A faulty rocker-arm oil control solenoid.
• Damaged wiring or a poor electrical connection.
• A short circuit or an abnormal voltage signal.
• A fault in the PCM driver circuit, which should only be considered after the external circuit has been tested.

2. Could These Faults Be Responsible for the Jerking?

Possibly, sir, but we should not assume that both codes are causing the same symptom.

P2649 directs attention to the VTEC control circuit, which should be investigated alongside the reported acceleration problem. However, the jerking could also involve the transmission, engine misfire, fuel delivery or another fault that has not yet been identified.

The fact that the problem becomes noticeable after driving for some time makes it important to assess the vehicle under the conditions in which the symptom occurs.

3. What Should Be Checked First?

I would recommend the following diagnostic sequence:

1. Complete Diagnostic Scan: Record all current, pending and stored codes, including freeze-frame data, before clearing anything.

2. PCM Power Supply: Check the relevant fuses, main relay, battery connections, grounds and PCM power-supply terminals. Confirm whether P0685 returns after the manufacturer’s prescribed verification procedure.

3. VTEC Control Circuit: Inspect the rocker-arm oil control solenoid connector and wiring. Test the solenoid and circuit according to Acura’s specifications.

4. Engine Oil Condition: Verify the oil level, correct oil specification and condition. Investigate any evidence of restricted oil flow or a VTEC hydraulic problem if the test results indicate it.

5. Acceleration and Transmission Assessment: Check for engine misfires, fuel-delivery problems and transmission-related codes. If necessary, monitor engine and transmission data during a controlled road test.

6. PCM Assessment: Consider an internal computer fault only after the relevant power supply, wiring, solenoid circuit and manufacturer-specific diagnostic checks have been completed.

4. Important Advice

Sir, I would not recommend replacing the brain box immediately or replacing the VTEC solenoid simply because P2649 is present.

The two codes may be related through an electrical issue, or they may represent separate faults. Proper testing is necessary to establish this.

Also, if the jerking becomes severe, the engine stalls, or the check-engine light flashes, avoid continued driving and arrange a proper inspection.

Ryan Automotive Limited Recommendation

At Ryan Automotive Limited, our approach is to identify the root cause before recommending expensive components.

To narrow this down further, kindly clarify two things:

1. When the vehicle jerks between 0–40 km/h, does the engine RPM rise without the vehicle accelerating properly, or does the entire vehicle shake as though the engine is misfiring?
2. After the vehicle has been driven for some time, does switching off the engine and allowing it to cool temporarily improve the problem?

These details will help us distinguish a possible engine-performance issue from a transmission-related concern and determine the next diagnostic steps.

You are welcome to contact Ryan Automotive Limited for a professional assessment along LASU–Isheri Road, Lagos.

RYAN AUTOMOTIVE LIMITED
Precision • Transparency • Excellence.

Please how much is this brain box? And where can I get the original one at a fair price?

My car is showing knock sensor code and after replacement it didn't correct/clear the electrician traced it brain box issue.

It's for Corolla 2010. My location is Enugu state.

Thank you.

This is the brain box

conqueror221:
This is the brain box

Google About, Ryan Automotive Limited

You are Ryan automotive. How much is the brain box? Original one oo

RyanAutomotive:
Google About, Ryan Automotive Limited

Lush100:
Good morning
I have unstable driving which usual feel that the tyres want to fall off especially when I enter a bump and about to take off.
Here are the things the mech says we might change.
Pls help sift through the prices.

Front hub= ₦65,000
Stabiliser linkage = ₦7000
Thyroid and socket = ₦25,000
Inner shaft rubber= ₦3,500
Ball joint (2)= ₦15,000
Back sock = ₦45,000
Absorber pad = ₦25,000
Front sock= ₦55,000

Why do you want people to come and verify these prices?
Different parts sellers sell their goods at different prices.
If your mechanic has gone thru the stress if getting prices and you feel he's marking up the prices, it shows you DO NOT trust him, but there's a very dangerous catch, you can trust him with your car that can be fixed poorly and can damage your life or main you?

If you don't trust your mechanic, find yourself another mechanic or start fixing your car yourself.

QED

By

kingreign:
Why do you want people to come and verify these prices?
Different parts sellers sell their goods at different prices.
If your mechanic has gone thru the stress if getting prices and you feel he's marking up the prices, it shows you DO NOT trust him, but there's a very dangerous catch, you can trust him with your car that can be fixed poorly and can damage your life or main you?

If you don't trust your mechanic, find yourself another mechanic or start fixing your car yourself.

QED

Thanks for your opinion.
It is noted .
The questions was not directed to your kind.
Since you couldn't help, pls ignore and allow those who would to do so.
Since you want to fix everything yourself or know it all yourself

QED

Lush100:
By
Thanks for your opinion.
It is noted .
The questions was not directed to your kind.
Since you couldn't help, pls ignore and allow those who would to do so.
Since you want to fix everything yourself or know it all yourself

QED

Then make contacts with part sellers. You can come to an agreement with your mechanic that you buy the parts and he fixes. if wetin you buy no make sense, na your wahala.

Good afternoon
My car temperature gauge easily go over the mid point when idling in traffic or moving too slowly like in bumpy roads. a certain time I turned on the AC and was at traffic, i realized the gauge was almost at the danger zone.

I checked the coolant level and noticed it is exactly at MIN line, ever since then I have been trying to get another coolant (pink/red) to top up whats already in the car, but I have been unable to get a coolant red one aside ABRO and I was advised not to use those as there are so many fakes.

please any recommendation/suggestions to stop the overheat or should I just removed the red coolant and use Total coolant (green)?

Quidaquo:
Good afternoon
My car temperature gauge easily go over the mid point when idling in traffic or moving too slowly like in bumpy roads. a certain time I turned on the AC and was at traffic, i realized the gauge was almost at the danger zone.

I checked the coolant level and noticed it is exactly at MIN line, ever since then I have been trying to get another coolant (pink/red) to top up whats already in the car, but I have been unable to get a coolant red one aside ABRO and I was advised not to use those as there are so many fakes.

please any recommendation/suggestions to stop the overheat or should I just removed the red coolant and use Total coolant (green)?

You forgot to mention the make and model of your car.
Anyways the problem is not about the type of coolant used. You have to diagnose and find out the root cause of the rising temp. It can be from your radiator cap, dirt in your radiator, water pump, cooling fan.

freeman500:
You forgot to mention the make and model of your car.
Anyways the problem is not about the type of coolant used. You have to diagnose and find out the root cause of the rising temp. It can be from your radiator cap, dirt in your radiator, water pump, cooling fan.

Thank you
it's a zotye sr9 which runs on a Mitsubishi 4G63S4T 2.0T, I notice both fans do come on too.