Pinpoint Test
- CHECK THE HVAC MODULE OUTPUT VOLTAGE
- Ignition ON.
- Press the POWER button on the HVAC controls.
- Measure:
Evaporator Temperature Sensor Evaporator Temperature Sensor C296 C296 Pin Circuit Measurement / Action Pin Circuit 1 VH406 (VT/BN) 2 RH111 (BY/BU) Is the voltage between 4.7 and 5.1 volts?
- Yes: INSTALL a new evaporator temperature sensor (part of 19850). REFER to Heater Core And Evaporator Core Housing . CLEAR the DTCs and REPEAT the self-test. If the DTC returns, GO to 7.
- No
: For DTC B1B71:11, GO to 5.
For DTC B1B71:15, GO to 2 .
- CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR A SHORT TO VOLTAGE
- CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR AN OPEN
- CHECK THE SIGNAL RETURN CIRCUIT FOR AN OPEN
- Measure:
HVAC Module Evaporator Temperature Sensor C228A C296 Pin Circuit Measurement / Action Pin Circuit 23 RH111 (GY/BU) 2 RH111 (GY/BU) Is the resistance less than 3 ohms?
- Yes: GO to 7.
- No : REPAIR the circuit.
- Measure:
- CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR A SHORT TO THE SIGNAL RETURN CIRCUIT
- CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR A SHORT TO GROUND
- CHECK FOR CORRECT HVAC MODULE OPERATION
- Ignition OFF.
- Disconnect and inspect all HVAC module connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect the HVAC module connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
- Yes: CHECK OASIS for any applicable TSBs . If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no TSBs address this concern, INSTALL a new HVAC module. REFER to Heating Ventilation Air Conditioning (HVAC) Module .
- No : The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.