LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2001 >> Impala LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P0481: Cooling Fan Relay No. 2 & 3 Control Circuit >> Diagnostic Procedures (Bonneville, Grand Prix, LeSabre & Park Avenue)

Diagnostic Procedures (Bonneville, Grand Prix, LeSabre & Park Avenue)

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
    2. NOTE: On Bonneville, LeSabre and Park Avenue, cooling fan 1 relay and cooling fan 2 relay are improperly identified in underhood fuse block.
  2. Install a scan tool. Turn ignition on, engine off. Using scan tool, command FANS HIGH SPEED on and off. If cooling fan Series/Parallel (S/P) relay and cooling fan 2 relays turn on and off with each command, see DIAGNOSTIC AIDS . If cooling fan S/P relay and cooling fan 2 relay do not turn on and off with each command, go to next step.
  3. Turn ignition off. Disconnect cooling fan 2 relay. Turn ignition on, engine off. Using test light connected to ground, probe battery voltage circuit of cooling fan 2 relay. If test light is on, go to next step. If test light is off, go to step  8.
  4. Connect a test light between high speed cooling fan relay control circuit (Light Blue wire) of cooling fan 2 relay and battery voltage circuit of cooling fan 2 relay. Using scan tool, command FANS HIGH SPEED on and off. If test light turns on and off with each command, go to step  9. If test light does not turn on and off, go to next step.
  5. If test light remains on with each command, go to step  7. If test light does not remain on with each command, go to next step.
  6. Check Dark Blue wire between cooling fan S/P relay, cooling fan 2 relay and PCM for short to voltage or open. If problem was found, repair as necessary. After repairs, go to step  12. If problem was not found, go to step  9.
  7. Check Dark Blue wire between cooling fan S/P relay, cooling fan 2 relay and PCM for short to ground. If problem was found, repair as necessary. After repairs, go to step  12. If problem was not found, go to step  9.
  8. Check battery voltage circuit of cooling fan S/P relay and cooling fan 2 relay for open or short to ground. If problem was found, repair as necessary. After repairs, go to step  12. If problem was not found, go to step  10.
  9. Check PCM connectors for poor connections. If problem was found, repair as necessary. After repairs, go to step  12. If problem was not found, go to step  11.
  10. Repair short to ground in Light Blue wire to cooling fan motor. After repairs, go to step  12.
  11. Replace PCM. Program replacement PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  12. Using scan tool, clear DTCs. Operate vehicle within code enable criteria. If DTC resets, go to step  2. If DTC does not reset, system is okay.
scientia non olet · About LEMON Manuals