P0690 trouble code definition
A P0690 trouble code is related to a vehicle’s engine control module (ECM) or powertrain control module and its direct power supply from the battery.
What the P0690 code means
P0690 is an OBD-II generic code for a high voltage problem with the power supply to the ECM/PCM. This means the vehicle’s computer is not receiving voltage that is within the manufacturer’s parameters.
What causes the P0690 code?
A P0690 code can have a variety of causes, but the most common are:
- Faulty ECM/PCM relay
- Blown ECM/PCM fuse
- Bad ECM/PCM grounds
- Bad battery
- Faulty battery cables
- Faulty ECM/PCM
What are the symptoms of the P0690 code?
How does a mechanic diagnose the P0690 code?
Because there are a number of potential causes for a P0690, your mechanic will start easy and clear the code and reset the ECM/PCM. If the code does not return, your mechanic will ensure all electrical connections for the battery and ECM/PCM are tight and it good condition - repairing as needed. Engine grounds will also be checked and cleaned as needed. If the code returns however, the ECM/PCM relay will need to be tested using a digital multi meter. If the relay is faulty, it will need to be replaced. In some cases, the ECM/PCM will need to be either reflashed or replaced.
Common mistakes when diagnosing the P0690 code
Because ECM/PCM replacements can be costly, this isn’t the best first move to make when dealing with a P0690. It’s important to test as many components as necessary and reset the ECM/PCM as needed.
How serious is the P0690 code?
This can either be serious or not so serious, and it depends on the condition of the vehicle when a P0690 is present. If there is a no-start condition, the problem could be more severe than if the code is illuminated and driving is normal.
What repairs can fix the P0690 code?
The most common repairs for a P0690 are as follows:
- Replacing the ECM/PCM relay
- Repairing ECM/PCM power wiring
- Replacing ECM/PCM fuses
- Replacing damaged battery cables
- Replacing the ECM/PCM
Additional comments for consideration regarding the P0690 code
If a P0690 is present, you may have other codes accompanying it. Check the order in which these codes come up on a OBD-II scanner as the ones higher above may be the route cause of the P0690.
Need help with a P0690 code?
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.