PSP Switch Signal Circuit Troubleshooting

Turn the ignition switch ON (II).
Measure voltage between ECM/PCM connector terminals A24 and E16.

Fig 1: Measuring Voltage Between ECM/PCM Connector Terminals A24 & E16

Is there less than 1.0 V?
1. YES - Go to step 3.
2. NO - Go to step 6.
Start the engine.
Turn the steering wheel to the full lock position.
Measure voltage between ECM/PCM connector terminals A24 and E16.
Is there battery voltage?
1. YES - The PSP switch signal is OK.
2. NO - Go to step 11.
Turn the ignition switch OFF.
Disconnect the PSP switch 2P connector.
Turn the ignition switch ON (II).
At the harness side, connect the PSP switch 2P connector terminals No. 1 and No. 2 with a jumper wire.

Fig 2: Connecting PSP Switch 2-Pin Connector Terminals No. 1 & No. 2
Measure voltage between ECM/PCM connector terminals A24 and E16.
Is there less than 1.0 V?
1. YES - Replace the PSP switch.
2. NO - Check for these problems:
  - An open in the wire between the ECM/PCM (E16) and the PSP switch.
  - An open in wire between the PSP switch and G201.
Turn the ignition switch OFF.
Disconnect the PSP switch 2P connector.
Turn the ignition switch ON (II).
Measure voltage between ECM/PCM connector terminals A24 and E16.

Fig 3: Measuring Voltage Between ECM/PCM Connector Terminals A24 & E16

Is there battery voltage?
1. YES - Replace the PSP switch.
2. NO - Go to step 15.
Turn the ignition switch OFF.
Disconnect ECM/PCM connector E (31P).
Check for continuity between body ground and ECM/PCM connector terminal E16.

Fig 4: Checking Continuity Between Body Ground & ECM/PCM Connector Terminal E16

Is there continuity?
1. YES - Repair short in the wire between the ECM/PCM (E16) and the PSP switch.
2. NO - Reprogram the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck (see ECM/PCM REPROGRAMMING AND SUBSTITUTION FOR TESTING ). If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.