LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 213 (Engine Controls - Self-Diagnostics - 3.0L) >> Diagnostic Tests >> DTC P0318: Rough Road Sensor Circuit >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: This chart diagnoses a non-ABS vehicle only. If this DTC is set on an ABS vehicle, C0040, C0041 or C0245 should also have set. If C0040 is not set, make sure the ECM is programmed for ABS. If it is, then go to the C0040 diagnostic to verify correct operation of the right front wheel speed sensor. If ABS DTC C0040, C0041 or C0245 is also set, diagnose that DTC first. See appropriate ANTI-LOCK article in BRAKES.
  1. Raise vehicle so wheels are off the ground. Locate wheel speed signal conditioner module located behind left gearshift center console trim panel. (Orange in color, looks like a relay). Turn ignition on, engine off. Using DVOM, measure voltage on White wire by backprobing circuit at the wheel speed signal conditioner module. Note voltage. Start engine and place transmission in drive. Rotate wheels at more than 3 MPH. Note voltage. If voltage changes from ignition voltage when the right front wheel was not moving to a lower or fluctuating voltage as wheel is spun, problem intermittent. See DIAGNOSTIC AIDS . If voltage does not change from ignition voltage when the right front wheel was not moving to a lower or fluctuating voltage as wheel is spun, go to next step.
  2. Turn ignition on, engine off. Remove wheel speed signal conditioner module. Connect test light between wheel speed conditioner module connector terminal No. 5 (Pink wire) and ground. If test light is on, go to next step. If test light is off, check BACKUP fuse (10-amp) located in underhood fuse block. Replace and retest if open. If fuse continues to open, locate short to ground in Pink wire. If fuse is okay, repair open in Pink wire between underhood fuse block and wheel speed signal conditioner module.
  3. Connect test light between wheel speed signal conditioner module connector terminal No. 1 (Black wire) and No. 5 (Pink wire). If test light is on, go to next step. If test light is off, repair open in Black wire between wheel speed signal conditioner module and ground.
  4. Using DVOM, measure voltage at wheel speed signal conditioner module connector terminal No. 2 (White wire). If ignition voltage is present, go to next step. If ignition voltage is not present, check White wire for open or short to ground between wheel speed signal conditioner module and ECM. If wire is okay, replace ECM.
  5. Connect test light between wheel speed signal conditioner module connector terminal No. 2 (White wire) and ground. If test light is on, repair short to voltage in White wire between wheel speed signal conditioner module and ECM. If test light is off, go to next step.
  6. Using DVOM, measure voltage on wheel speed signal conditioner module connector terminal No. 3 (Tan wire), then on terminal No. 4 (Dark Green wire). If voltage is present on either circuit, Tan wire or Dark Green wire is shorted to voltage. Disconnect right front wheel speed sensor and remeasure voltage to determine which wire is shorted.
  7. Measure resistance between wheel speed signal conditioner connector terminal No. 3 (Tan wire) and ground, then between terminal No. 4 (Dark Green wire) and ground. If resistance is less than 100 ohms for either measurement, repair short to ground in wire with less than 100 ohms resistance. If resistance was not less than 100 ohms for either wire, go to next step.
  8. Measure resistance between wheel speed signal conditioner module connector terminals No. 3 (Tan wire) and No. 4 (Dark Green wire). If resistance is 1000-2000 ohms, go to next step. If resistance is not 1000-2000 ohms, check Tan wire and Dark Green wire for open and short to each other. If wires are okay, replace right front wheel speed sensor.
  9. Using DVOM, measure AC voltage between wheel speed signal conditioner module connector terminals No. 3 (Tan wire) and No. 4 (Dark Green wire) while spinning right front wheel. If AC voltage is present, check each circuit at wheel speed signal conditioner module connector. If connector is okay, replace wheel speed signal conditioner module. If AC voltage is not present, check sensor for tightness. Retest if sensor was loose. Check reluctor wheel for damage and missing teeth. If reluctor wheel checks okay, replace right front wheel speed sensor.
scientia non olet · About LEMON Manuals