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Home >> Chevrolet >> 2001 >> Impala Base, 3.8 K >> Repair and Diagnosis >> External Pages >> Different car >> Section 36 (HVAC Systems - Automatic) >> Diagnostic Tests >> DTC B0446: Right-Side Temperature Actuator Shorted Or Open >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue. However, it is still accessible from the selected car via links, so may be relevant.
  1. If diagnostic system check was not performed, go to DIAGNOSTIC SYSTEM CHECK . If diagnostic system check was performed, go to next step.
  2. Install scan tool. Turn ignition on. Using scan tool, command RIGHT MIX MOTOR ON and OFF to display maximum and minimum counts of RH MIX MOTOR POSITION FEEDBACK in HEATING and AIR CONDITIONING, SPECIAL FUNCTIONS, MISCELLANEOUS TEST list. Subtract minimum RH MIX MOTOR POSITION FEEDBACK from maximum RH MIX MOTOR POSITION FEEDBACK. If result of calculation indicates actual travel of right air temperature actuator is within 147-251 counts, problem is intermittent. If result of calculation does not indicate actual travel of right air temperature actuator is within 147-251 counts, go to next step.
  3. Check ignition voltage circuit of right air temperature actuator for an open or high resistance. Repair wiring as necessary. If wiring is okay, go to next step.
  4. Check right air temperature door control circuit of right air temperature actuator for open, high resistance, short to ground or short to voltage. Repair wiring as necessary. If wiring is okay, go to next step.
  5. Check 5-volt reference circuit of right air temperature actuator for open circuit or high resistance. Repair wiring as necessary. If wiring is okay, go to next step.
  6. Ensure right air temperature actuator connector and HVAC control module connectors are connected. Turn ignition on. Using scan tool, observe RH MIX MOTOR POSITION FEEDBACK DATA parameter. Connect 3-amp fused jumper wire between air temperature door control circuit and 5-volt reference circuit of right air temperature actuator (drives actuator full HOT). Remove and reconnect jumper wire between air temperature door control circuit and ground circuit of right air temperature actuator (drives actuator full COOL). If right air temperature actuator drive shaft rotates and counts change, go to next step. If right air temperature actuator drive shaft does not rotate and counts do not change, go to step  9.
  7. Measure voltage between right air temperature door control circuit of right air temperature actuator and ground. Using scan tool, command RIGHT TEMP DOOR position from HOT to COLD. If voltage measures near 5 volts when increasing temperature, near zero volts when decreasing or near 2.5 volts when stationary, go to next step. If voltage does not measure near 5 volts when increasing temperature, near zero volts when decreasing or near 2.5 volts when stationary, go to step  10.
  8. Check right air temperature door and right air temperature actuator for misaligned actuator, broken or binding linkages, obstruction, and missing or misaligned seals.
  9. Check for poor connection at harness connector of right air temperature actuator. Repair connector as necessary, then go to step  13. If connector is okay, go to step  11.
  10. Check for poor connection at harness connector of HVAC control module. Repair connector as necessary, then go to step  13. If connector is okay, go to step  12.
  11. Replace right air temperature actuator. See TEMPERATURE ACTUATORS  under REMOVAL & INSTALLATION. After repairs are complete, go to step  13.
  12. Replace HVAC control module. See HVAC CONTROL MODULE  under REMOVAL & INSTALLATION. After repairs are complete, go to next step.
  13. Clear DTCs. Operate vehicle. Check for DTCs. If DTC B0446 is still present, go to step  2. If DTC does not reset, system is okay.
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