DTC 311 & DTC 312: Front Wheel Sensor Signal - Circuit Fault

WARNING: This page is about a different car, the 1996 Volvo 850. However, it is still accessible from the selected car via links, so may be relevant.

Check if additional DTCs are present. If only DTCs 311 and 312 are present, check if fault is permanent or intermittent. If fault is permanent, go to step 3). If fault is intermittent, go to step 11). If DTCs 311 or 312, and DTCs 211-214, and 221-224 or 321-324 are present (for same wheel), go to next step.
Turn ignition on. Use scan tool and enter running values, list No. 1. Raise and support vehicle so relevant wheel is off the ground. Spin wheel. If wheel speed is displayed on scan tool, go to step 11). If wheel speed is not displayed on scan tool, go to next step.
Turn ignition off. Disconnect ABS control module. Connect breakout box. Connect ohmmeter between breakout box pins No. 4 and 11 (DTC 311), or between pins No. 3 and 18 (DTC 312). If ohmmeter reads 1040-1160 ohms, go to step 8). If ohmmeter does not read 1040-1160 ohms, go to next step.
Remove wheels for better access. Clean around wheel sensor connector. Disconnect wheel sensor 2-pin connector. Connect ohmmeter between connector terminals No. 1 and 2. If ohmmeter reads 1040-1160 ohms, go to next step. If ohmmeter does not read 1040-1160 ohms, replace wheel sensor.
Ensure ignition is off. Ensure wheel sensor and ABS control module connectors are disconnected. Connect ohmmeter between wheel sensor connector terminal No. 2 (Black wire) and breakout box pin No. 4 (DTC 311), or between wheel sensor connector terminal No. 2 (Black wire) and breakout box pin No. 3 (DTC 312). If about zero ohms are present, go to next step. If about zero ohms are not present, check for an open circuit in wiring between wheel sensor connector and control module.
Connect ohmmeter between breakout box pins No. 1 and 11 (DTC 311), or pins No. 1 and 18 (DTC 312). If ohmmeter reads about zero ohms, go to next step. If ohmmeter does not read about zero ohms, check for open circuit in wiring between wheel sensor connector and control module.
Connect ohmmeter between breakout box pins No. 4 and 11 (DTC 311), or pins No. 3 and 18 (DTC 312). If ohmmeter reads about zero ohms, fault was caused by poor contact in wheel sensor connector. Repair as necessary. If ohmmeter does not read about zero ohms, check for short circuit in wiring between wheel sensor and control module.
Turn ignition off. Reconnect ABS control module. Turn ignition on. Connect voltmeter between breakout box pins No. 8 and 4 (DTC 311), or pins No. 8 and 3 (DTC 312). If about 2.3 volts are present, fault was caused by poor contact at control module connector. Repair as necessary. If less than 2.3 volts are present, go to next step. If greater than 2.3 volts are present, go to step 10).

Check for a short to ground in wiring between wheel sensor connector terminals and ABS control module. See DTC 311 & 312 TERMINAL IDENTIFICATION table. Refer to wiring diagram for control module terminal identification. Repair as necessary.

DTC 311 & 312 TERMINAL IDENTIFICATION

Wheel Sensor Terminal No.		Control Module Terminal No.
DTC 311
2		4
1		11
DTC 312
2		3
1		18

Check for a short to voltage in wiring between wheel sensor connector terminals and ABS control module. See DTC 311 & 312 TERMINAL IDENTIFICATION table. Repair as necessary.
If fault is intermittent, check wheel sensor and control module connectors for poor terminal contact. Repair as necessary. Check for intermittent opens, short to ground, or short to voltage in wiring between wheel sensor connector and control module. See DTC 311 & 312 TERMINAL IDENTIFICATION table. Repair as necessary.