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Code 31, Left Front Abs Valve

  1. Turn ignition off. Unplug ABS/AWD control unit. Check continuity between pins No. 19 and 17, and between pins No. 19 and 23 of ABS/AWD control unit wiring harness. If necessary, unplug ABS hydraulic control unit to help isolate open circuit.
  2. Remove 7-pin ABS valve relay from ABS hydraulic control unit. Check for a short circuit to ground or battery voltage at pin No. 19 of ABS/AWD control unit wiring harness. If necessary, break continuity of circuit to help isolate short circuit.
  3. Check resistance between pin No. 19 of ABS/AWD control unit wiring harness and pin No. 30 of ABS valve relay base. See Figure . Resistance should be 1-2 ohms. If resistance is correct, go to step 5).
  4. If resistance is incorrect, remove 12-pin connector from ABS hydraulic control unit. Check resistance of ABS solenoid valve between pins No. 1 and 4 of ABS hydraulic control unit. See Figure . Resistance should be 0.7-1.7 ohms. If resistance is incorrect, replace ABS hydraulic control unit.
  5. Reconnect all disconnected components. Push back protective cap at valve block assembly connector. Turn ignition off, then back on. Ensure voltage is present at pin No. 1 and 2 (ABS valve relay energized). If voltage is present, perform Code 34 tests. If no voltage is present, replace ABS/AWD control unit.
NOTE: If connector for solenoid valves (ABS or differential lock) is disconnected while ignition is turned on, ABS valve relay is de-energized. Even if connector is plugged back in, relay will not be re-energized until ignition is switched off and on again.
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