Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
PSP Switch Signal Circuit Troubleshooting
- Start the engine, and let it idle.
- Align the steering wheel straight ahead.
- Check the PSP SWITCH in the DATA LIST with the HDS.
Does it indicate ON?
YES -Go to step 4.
NO -Go to step 14.
- Turn the steering wheel to the full lock position.
- Check the PSP SWITCH in the DATA LIST with the HDS.
Does it change to OFF?
YES -The PSP switch signal circuit is OK.
NO -Go to step 6.
- Turn the ignition switch to LOCK (0).
- Disconnect the PSP switch 2P connector.
- Start the engine.
- Check the PSP SWITCH in the DATA LIST with the HDS.
Does it change to OFF?
YES -Replace the PSP switch.
NO -Go to step 10.
- Turn the ignition switch to LOCK (0).
- Jump the SCS line with the HDS.
- Disconnect PCM connector A (44P).
- Check for continuity between PSP switch 2P connector terminal No. 1 and body ground.
Is there continuity?
YES -Repair a short in the wire between the PCM (A22) and the PSP switch.
NO -Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
- Turn the ignition switch to LOCK (0).
- Disconnect the PSP switch 2P connector.
- Connect PSP switch 2P connector terminals No. 1 and No. 2 with a jumper wire, then start the engine.
- Check the PSP SWITCH in the DATA LIST with the HDS.
Does it change to ON?
YES -Replace the PSP switch.
NO -Go to step 18.
- Turn the ignition switch to LOCK (0).
- Remove the jumper wire from the PSP switch 2P connector.
- Jump the SCS line with the HDS.
- Disconnect PCM connector A (44P).
- Connect PSP switch 2P connector terminal No. 1 to body ground with a jumper wire.
- Check for continuity between body ground and PCM connector terminal A22.
Is there continuity?
YES -Go to step 24.
NO -Repair an open in the wire between the PSP switch and the PCM (A22).
- Check for continuity between PSP switch 2P connector terminal No. 2 and body ground.
Is there continuity?
YES -Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM (see PCM REPLACEMENT ).
NO -Repair an open in the wire between the PSP switch and G401.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.