Power Steering Pressure (PSP) Switch Signal
- Connect ECM test harness between ECM and ECM connectors. Measure voltage between terminals B5 (positive) and D22 (negative). If voltage is less than one volt, go to step 3. If battery voltage exists, disconnect 2-wire connector on PSP switch located on power steering pump. Connect jumper between Green and Green/White wire terminals.
- If battery voltage is present, replace PSP switch. If less than one volt is present, repair open in Green wire (between ECM terminal B5 and PSP switch) or Green/White wire leading to ECM terminal D22.
- Start engine. Turn steering wheel slowly. Measure voltage between ECM test harness terminals B5 (positive) and D22 (negative) while wheel is being turned. If battery voltage exists, PSP signal is okay.
- If battery voltage is not present, disconnect ECM test harness connector "B" to main wire harness only. DO NOT disconnect from ECM. Turn ignition on. If 12 volts is not present, try a known-good ECM. If problem goes away, replace ECM.
- If battery voltage exists, reconnect connector "B" to main harness. Unplug connector from PSP switch. Check Green wire for battery voltage. If battery voltage is present, replace P/S oil pressure switch. If battery voltage is not present, repair short in Green wire between ECM terminal B5 and PSP switch.