CODE 31 - A/T FI SIGNAL B
1. Turn ignition off. Reset ECU by removing BACK-UP fuse in under-hood relay box for 10 seconds. Road test vehicle. Drive several miles so that transmission upshifts and downshifts several times. Verify if CHECK ENGINE light is on and if LED is flashing Code 31. If LED is flashing Code 31, go to next step. If LED is not flashing Code 31, problem is intermittent, system is okay at this time.
2. Turn ignition off. Connect ECU Test Harness between ECU and ECU connector. See Fig. 7 . Disconnect 22-wire connector from A/T control unit. Check for continuity between ECU terminal B4 and ground.
3. If continuity exists. repair short in Green wire between ECU terminal B4 and A/T control unit. If continuity did not exist. check for continuity on White/Red wire between ECU terminal B4 and A/T control unit connector.
4. If continuity does not exist, repair open in Green wire between ECU terminal B4 and A/T control unit. If continuity did exist, substitute a known good ECU. If condition is corrected, replace original ECU.
Friday, October 31st, 2008 AT 9:46 AM