DTC 31-38: Modulator Unit Solenoid Malfunction
- Turn ignition off, then on again. Check DTC(s). If DTC 54 is set, diagnose that DTC. See DTC 54: FAIL-SAFE RELAY MALFUNCTION . If DTC 54 is not set, turn ignition off. Disconnect 24-pin modulator unit connector and 12-pin ABS/TCS control unit connector "C". Go to next step.
- Using a DVOM, check for continuity to ground at appropriate ABS/TCS control unit connector "C" terminal. See ABS/TCS COMPONENT TERMINAL IDENTIFICATION table. See Figure. If continuity does not exist, leave DVOM connected and go to next step. If continuity exists, locate and repair short to ground in affected circuit between ABS/TCS control unit and modulator unit.ABS/TCS COMPONENT TERMINAL IDENTIFICATION
DTC ABS/TCS Control Unit Connector "C" Terminal ABS Modulator Unit Terminal Wire Color 31 No. 11 No. 11 Red/Black 32 No. 6 No. 19 Yellow/Black 33 No. 9 No. 14 Red/Blue 34 No. 4 No. 22 Yellow/Blue 35 No. 8 No. 13 Red/White 36 No. 3 No. 21 Yellow/White 37 No. 10 No. 12 Red/Green 38 No. 5 No. 20 Yellow/Green - Reconnect modulator unit connector. With DVOM still connected to appropriate terminal of ABS/TCS control unit connector for DTC displayed, check continuity to ground. If continuity exists, solenoid in modulator unit is shorted to ground. Replace modulator unit. If continuity does not exist, go to next step.
- Disconnect 24-pin modulator unit connector. Connect a jumper wire from ground to appropriate modulator unit connector terminal for DTC displayed. See ABS/TCS COMPONENT TERMINAL IDENTIFICATION table. See Fig 1. Using DVOM, check for continuity between ground and appropriate ABS/TCS control unit 12-pin connector "C" terminal. If continuity does not exist, locate and repair open circuit in wire between ABS/TCS control unit and modulator unit. If continuity exists, go to next step.
- Remove jumper wire from modulator unit connector. Reconnect modulator unit connector. Using fused jumper wire, ground terminal No. 2 (Brown/Black wire) of ABS fail-safe relay (in underdash relay block). See Fig 2. Using DVOM, check resistance between ground and appropriate ABS/TCS control unit connector "C" terminal for specific DTC set. For DTCs 31, 33, 35 and 37 (inlet solenoid), resistance should be 8-10 ohms. For DTCs 32, 34, 36 and 38 (outlet solenoid), resistance should be 3-5 ohms. If resistance is not as specified, replace modulator unit. If resistance is as specified, go to next step.
- Disconnect 24-pin modulator unit connector. Remove jumper wire from terminal No. 2 of ABS fail-safe relay. Using DVOM, check for continuity between appropriate terminal of ABS/TCS control unit connector "C" for specific DTC set and all other solenoid circuit terminals. See ABS/TCS COMPONENT TERMINAL IDENTIFICATION table. If continuity exists, repair short circuit in appropriate wires between modulator unit and ABS/TCS control unit. If continuity does not exist, go to next step.
- Reconnect modulator unit connector. Measure resistance between appropriate terminal of ABS/TCS control unit connector "C" for specific DTC set and all other solenoid circuit terminals. If resistance is less than 3 ohms, replace modulator unit. If resistance is more than 3 ohms, check for poor connection at ABS/TCS control unit. If connection is okay, replace ABS/TCS control unit.