4-Faulty Back-Up Power Supply

DIAGNOSIS
- Faulty back-up power supply harness
- Faulty PCM (Power Steering Control Module)

SYMPTOM
- Trouble contents are not retained in memory.





1. Check PCM back-up power supply.
a. Disconnect connectors from PCM.





b. Measure voltage across PCM connector and GND. Connector & Terminal/Specified voltage: (R91) No. 15-Body/10 V, or more. If fuse No. 25 is blown, it can be identified by shorted circuit between F/B (fuse block) and PCM.
2. Check and repair back-up power supply harness or connector as necessary.





Measure voltage across connector (F16) terminal and GND. Connector & Terminal/Specified voltage: (F16) No. 2-Body/10 V, or more
- OK - Open circuit between M/B and PCM (including SMJ)
- NOT OK - Open circuit between connectors (F17) and (F16)