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B1B71:11




Climate Control System

Pinpoint Test G: DTCs B1B71:11 and 15

Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. [1][2]Diagrams By Number

Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. [1][2]Diagrams By Number

Normal Operation

Under normal operation, the evaporator discharge air temperature sensor receives a ground from the HVAC module through circuit RH111 (GY/BU). A 5-volt reference voltage is supplied to the evaporator discharge air temperature sensor from the HVAC module through circuit VH406 (VT/BN).

- DTC B1B71:11 (Evaporator Temperature Sensor: Circuit Short to Ground)- The module senses excessive voltage drop on the sensor reference voltage circuit, indicating a short directly to ground.

- DTC B1B71:15 (Evaporator Temperature Sensor: Circuit Short to Battery or Open)- The module senses no voltage drop on the sensor reference voltage circuit, indicating a short directly to voltage or an open circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Evaporator discharge air temperature sensor

- HVAC module

PINPOINT TEST G : DTCs B1B71:11 AND 15

G1 CHECK THE SENSOR RESISTANCE

- Ignition OFF.

- Disconnect: HVAC Module- Electronic Manual Temperature Control (EMTC) C2357a.

- Disconnect: HVAC Module- Dual Automatic Temperature Control (DATC) C2356a.

- Measure the resistance between HVAC module- EMTC (Electronic Manual Temperature Control) C2357A-6 or HVAC module- DATC (Dual Automatic Temperature Control) C2356A-6, circuit VH406 (VT/BN), harness side and HVAC module- EMTC (Electronic Manual Temperature Control) C2357A-10 or HVAC module- DATC (Dual Automatic Temperature Control) C2356A-10, circuit RH111 (GY/BU), harness side.





- Compare the measurement to the chart and table of the Evaporator Discharge Air Temperature Sensor component test.

Is the resistance within the specified values for the temperatures?

Yes

For DTC B1B71:11, GO to G2.

For DTC B1B71:15, GO to G3.

No

For DTC B1B71:11, GO to G4.

For DTC B1B71:15, GO to G5.

G2 CHECK CIRCUIT VH406 (VT/BN) FOR A SHORT TO GROUND

- Measure the resistance between HVAC module- EMTC (Electronic Manual Temperature Control) C2357A-6 or HVAC module- DATC (Dual Automatic Temperature Control) C2356A-6, circuit VH406 (VT/BN), harness side and ground.





Is the resistance greater than 10,000 ohms?

Yes
GO to G7.

No
REPAIR circuit VH406 (VT/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

G3 CHECK CIRCUIT VH406 (VT/BN) FOR A SHORT TO VOLTAGE

- Ignition ON.

- Measure the voltage between ground and HVAC module- EMTC (Electronic Manual Temperature Control) C2357A-6 or HVAC module- DATC (Dual Automatic Temperature Control) C2356A-6, circuit VH406 (VT/BN), harness side and ground.





Is any voltage present?

Yes
REPAIR circuit VH406 (VT/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

No
GO to G7.

G4 CHECK CIRCUIT VH406 (VT/BN) FOR A SHORT TO CIRCUIT RH111 (GY/BU)

NOTE: Instrument panel removal is required to disconnect the sensor. Before carrying out this test step, visually inspect the wiring between the HVAC module and sensor for shorts. If no damage is visually evident, proceed with the test.

- Ignition OFF.

- Disconnect: Evaporator Discharge Air Temperature Sensor C2295.

- Measure the resistance between HVAC module- EMTC (Electronic Manual Temperature Control) C2357A-6 or HVAC module- DATC (Dual Automatic Temperature Control) C2356A-6, circuit VH406 (VT/BN), harness side and HVAC module- EMTC (Electronic Manual Temperature Control) C2357A-10 or HVAC module- DATC (Dual Automatic Temperature Control) C2356A-10, circuit RH111 (GY/BU), harness side.





Is the resistance greater than 10,000 ohms?

Yes
INSTALL a new evaporator discharge air temperature sensor. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

No
REPAIR circuit VH406 (VT/BN) for a short to circuit RH111 (GY/BU). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

G5 CHECK CIRCUITS VH406 (VT/BN) FOR AN OPEN

NOTE: Instrument panel removal is required to disconnect the sensor. Before carrying out this test step, visually inspect the wiring between the HVAC module and sensor for opens. If no damage is visually evident, proceed with the test.

- Ignition OFF.

- Disconnect: Evaporator Discharge Air Temperature Sensor C2295.

- Measure the resistance between HVAC module- EMTC (Electronic Manual Temperature Control) C2357A-6 or HVAC module- DATC (Dual Automatic Temperature Control) C2356A-6, circuit VH406 (VT/BN), harness side and inline (EMTC (Electronic Manual Temperature Control)) C211-13 or (DATC (Dual Automatic Temperature Control)) inline C213-13, circuit VH406 (VT/BN), instrument panel harness side.





- Measure the resistance between inline (EMTC (Electronic Manual Temperature Control)) C211-13 or (DATC (Dual Automatic Temperature Control)) inline C213-13, circuit VH406 (VT/BN), HVAC case harness side and evaporator discharge air temperature sensor C2295-1, circuit VH406 (VT/BN), harness side.





Is the resistance less than 5 ohms?

Yes
GO to G6.

No
REPAIR circuit VH406 (VT/BN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

G6 CHECK CIRCUITS RH111 (GY/BU) FOR AN OPEN

- Measure the resistance between HVAC module- EMTC (Electronic Manual Temperature Control) C2357A-10 or HVAC module- DATC (Dual Automatic Temperature Control) C2356A-10, circuit RH111 (GY/BU), harness side and inline (EMTC (Electronic Manual Temperature Control)) C211-15 or (DATC (Dual Automatic Temperature Control)) inline C213-15, circuit RH111 (GY/BU), instrument panel harness side.





- Measure the resistance between inline (EMTC (Electronic Manual Temperature Control)) C211-15 or (DATC (Dual Automatic Temperature Control)) inline C213-15, circuit RH111 (GY/BU), HVAC case harness side and evaporator discharge air temperature sensor C2295-2, circuit RH111 (GY/BU), harness side.





Is the resistance less than 5 ohms?

Yes
INSTALL a new evaporator discharge air temperature sensor. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

No
REPAIR circuit RH111 (GY/BU) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

G7 CHECK THE MODULE CONNECTION

- Inspect the module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.


- Connect and correctly seat all the HVAC module connectors.

- Clear the DTCs.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new HVAC module. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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