P1631 Lexus Code - Communication Error from ECM to VSC
Quick Answer
The Engine Control Module (ECM) sends signals such as A/T information signals, dynamic radar cruise control operation signals, and brake operation demand signals to the Skid Control Electronic Control Unit (ECU) (Brake Actuator Assembly) when the dynamic radar cruise control is operating. Common causes include Faulty Skid Control ECU (Brake Actuator Assembly), Skid Control ECU harness is open or shorted, Skid Control ECU circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1631 Lexus indicates Communication Error from ECM to VSC.
- Common causes
- Common causes include Faulty Skid Control ECU (Brake Actuator Assembly), Skid Control ECU harness is open or shorted, Skid Control ECU circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P1631 Lexus Description
While the vehicle speed is 40 km/h (25 mph) or more and the dynamic radar cruise control system is operating (vehicle-to-vehicle distance control mode), if the ECM continuously receives a logical error signal from the skid control ECU (brake actuator assembly) for approximately 1 second or more the Diagnostic Trouble Code (DTC) will be set.
What are the Possible Causes of the DTC P1631 Lexus?
- Faulty Skid Control ECU (Brake Actuator Assembly)
- Skid Control ECU harness is open or shorted
- Skid Control ECU circuit poor electrical connection
- Faulty Engine Control Module (ECM)
How to Fix the DTC P1631 Lexus?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1631 Lexus code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P1631 Lexus Code
1. What does the OBDII code P1631 mean in a Lexus?
P1631 indicates a communication error between the Engine Control Module (ECM) and the Vehicle Stability Control (VSC) system.
2. What are the common symptoms of P1631 in a Lexus?
Common symptoms include the VSC or Check Engine Light illuminating, reduced stability control functionality, and possible engine performance issues.
3. What causes the P1631 code to appear in a Lexus?
This code can be caused by faulty wiring or connectors between the ECM and VSC, a malfunctioning ECM, or a defective VSC module.
4. Can a weak battery cause the P1631 code in a Lexus?
Yes, a weak or failing battery can disrupt communication between the ECM and VSC, triggering the P1631 code.
5. How do you diagnose a P1631 code in a Lexus?
Diagnosis involves scanning for additional codes, inspecting wiring and connectors, and testing the ECM and VSC modules for proper communication.
6. Is it safe to drive a Lexus with a P1631 code?
While the vehicle may still be drivable, stability control systems may not function properly, posing a safety risk in certain driving conditions.
7. How can you fix the P1631 code in a Lexus?
Repairs may include fixing damaged wiring, replacing a faulty ECM or VSC module, or addressing other related electrical issues.
8. Can clearing the code fix the P1631 issue in a Lexus?
Clearing the code may temporarily turn off the warning light, but it won’t solve the underlying communication problem.
9. How much does it cost to repair the P1631 code in a Lexus?
Repair costs depend on the root cause, ranging from $50 for simple wiring fixes to $1,000 or more for ECM or VSC module replacement.
10. Can a software update fix the P1631 code in a Lexus?
In some cases, a software update for the ECM or VSC module may resolve communication errors, but this depends on the specific vehicle and issue.
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