DTC 31: Engine Retard Command Signal
NOTE:
If MIL indicator is on, go to SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.2TL article in ENGINE PERFORMANCE. If ABS indicator is on, retrieve ABS DTCs and go to ABS DIAGNOSTIC TESTS .
- Disconnect 12-pin (1999) or 20-pin (2000-2001) PCM connector "E" and ABS/TCS control unit 16-pin connector "B". Using DVOM, check for continuity on Blue wire between ground and PCM harness connector "E" terminals No. 3 (1999) or 7 (2000-2001). See Fig 1. If continuity is indicated, repair short circuit to ground on Blue wire between PCM harness connector "E" terminal No. 3 (1999) or 7 (2000-2001) and ABS/TCS control unit 16-pin connector "B" terminal No. 10. See Figure. See WIRING DIAGRAMS . If continuity is not indicated, go to next step.NOTE: Use an analog voltmeter set to 10-volt scale for following steps.
- Reconnect 12-pin (1999) or 20-pin (2000-2001) PCM connector "E". Start engine. Measure voltage between ground and 12-pin (1999) or 20-pin (2000-2001) PCM connector "E" terminal No. 3 (1999) or No. 7 (2000-2001). If voltage reading is about 2.5 volts, go to next step. If voltage is not as specified, check for poor connections at PCM. If connections are okay, substitute known-good PCM and retest system.
- Measure voltage between ground and ABS/TCS control unit 16-pin connector "B" terminal No. 10. If voltage reading is about 2.5 volts, check for poor connections at ABS/TCS control unit. If connections are okay, substitute known-good ABS/TCS control unit and retest system. If voltage reading is not as specified, repair open circuit in Blue wire between PCM harness connector "E" terminal No. 3 (1999) or 7 (2000-2001) and ABS/TCS control unit 16-pin connector "B" terminal No. 10.