Pinpoint Test P: Temperature Control Is Inoperative/Does Not Operate Correctly - EMTC
Climate Control System
Pinpoint Tests
Pinpoint Test P: Temperature Control is Inoperative/Does Not Operate Correctly - EMTC
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, to rotate the blend door actuator, the HVAC module supplies voltage to the blend door actuator motor through circuit CH233 (VT/BN), and supplies ground through circuit CH234 (YE/GN). To reverse the blend door actuator rotation, the HVAC module reverses the voltage and ground circuits.
The blend door actuator feedback resistors are supplied a ground from the HVAC module by circuit RH111 (GY/BU) and a 5-volt reference voltage circuit LH111 (BN/WH). The HVAC module reads the voltage on circuit VH439 (GY/VT) to determine the blend door actuator position, by the position of the actuator feedback resistor wiper arm.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Blend door actuator motor
- HVAC module - Electronic Manual Temperature Control (EMTC)
- Stuck or bound linkage or door
PINPOINT TEST P: TEMPERATURE CONTROL IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - EMTC
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P1 CHECK THE FEEDBACK POTENTIOMETER TOTAL RESISTANCE
- Ignition OFF.
- Disconnect: HVAC Module - EMTC C2357a.
- Measure the resistance between HVAC module - EMTC C2357a-5, circuit LH111 (BN/WH), harness side and HVAC module - EMTC C2357a-15, circuit RH111 (GY/BU), harness side.
- Is the resistance between 4,000 and 6,000 ohms?
Yes
GO to P2.
No
If resistance is greater than 6,000 ohms, GO to P4.
If resistance is less than 4,000 ohms, GO to P5.
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P2 CHECK THE POTENTIOMETER LOW-SIDE RESISTANCE
- Measure the resistance between HVAC module - EMTC C2357a-15, circuit RH111 (GY/BU), harness side and HVAC module - EMTC C2357a-18, circuit VH439 (GY/VT), harness side.
- Is the resistance between 1 and 10,000 ohms?
Yes
GO to P3.
No
If resistance is greater than 10,000 ohms, GO to P6.
If resistance is less than 1 ohm, GO to P7.
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P3 CHECK THE POTENTIOMETER HIGH-SIDE RESISTANCE
- Measure the resistance between HVAC module - EMTC C2357a-5, circuit LH111 (BN/WH), harness side and HVAC module - EMTC C2357a-18, circuit VH439 (GY/VT), harness side.
- Is the resistance between 1 and 10,000 ohms?
Yes
GO to P9.
No
If resistance is greater than 10,000 ohms, INSTALL a new door actuator. TEST the system for normal operation.
If resistance is less than 1 ohm, GO to P8.
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P4 CHECK CIRCUITS LH111 (BN/WH) AND RH111 (GY/BU) FOR AN OPEN
NOTE: Due to limited connector accessibility, before carrying out this test step, visually inspect the wiring between the HVAC module and actuator for opens or shorts. If no damage is visually evident, proceed with the test.
- Disconnect: LH Blend Door Actuator C2091.
- Measure the resistance between HVAC module - EMTC C2357a-5, circuit LH111 (BN/WH), harness side and LH blend door actuator C2091-10, circuit LH111 (BN/WH), harness side.
- Measure the resistance between HVAC module - EMTC C2357a-15, circuit RH111 (GY/BU), harness side and LH blend door actuator C2091-7, circuit RH111 (GY/BU), harness side.
- Are the resistances less than 5 ohms?
Yes
INSTALL a new door actuator. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
REPAIR circuit LH111 (BN/WH) or RH111 (GY/BU) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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P5 CHECK CIRCUITS RH111 (GY/BU) AND LH111 (BN/WH) FOR A SHORT TOGETHER
NOTE: Due to limited connector accessibility, before carrying out this test step, visually inspect the wiring between the HVAC module and actuator for opens or shorts. If no damage is visually evident, proceed with the test.
- Disconnect: LH Blend Door Actuator C2091.
- Measure the resistance between HVAC module - EMTC C2357a-5, circuit LH111 (BN/WH), harness side and HVAC module - EMTC C2357a-15, circuit RH111 (GY/BU), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new door actuator. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
REPAIR circuits RH111 (GY/BU) and LH111 (BN/WH) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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P6 CHECK CIRCUIT VH439 (GY/VT) FOR AN OPEN
NOTE: Due to limited connector accessibility, before carrying out this test step, visually inspect the wiring between the HVAC module and actuator for opens or shorts. If no damage is visually evident, proceed with the test.
- Disconnect: LH Blend Door Actuator C2091.
- Measure the resistance between HVAC module - EMTC C2357a-18, circuit VH439 (GY/VT), harness side and LH blend door actuator C2091-9, circuit VH439 (GY/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new door actuator. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
REPAIR circuit VH439 (GY/VT) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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P7 CHECK CIRCUIT RH111 (GY/BU) FOR A SHORT TO CIRCUIT VH439 (GY/VT)
NOTE: Due to limited connector accessibility, before carrying out this test step, visually inspect the wiring between the HVAC module and actuator for opens or shorts. If no damage is visually evident, proceed with the test.
- Disconnect: LH Blend Door Actuator C2091.
- Measure the resistance between HVAC module - EMTC C2357a-15, circuit RH111 (GY/BU), harness side and HVAC module - EMTC C2357a-18, circuit VH439 (GY/VT), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new door actuator. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
REPAIR circuits RH111 (GY/BU) and VH439 (GY/VT) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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P8 CHECK CIRCUIT LH111 (BN/WH) FOR A SHORT TO CIRCUIT VH439 (GY/VT)
NOTE: Due to limited connector accessibility, before carrying out this test step, visually inspect the wiring between the HVAC module and actuator for opens or shorts. If no damage is visually evident, proceed with the test.
- Disconnect: LH Blend Door Actuator C2091.
- Measure the resistance between HVAC module - EMTC C2357a-5, circuit LH111 (BN/WH), harness side and HVAC module - EMTC C2357a-18, circuit VH439 (GY/VT), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new door actuator. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
REPAIR circuits LH111 (BN/WH) and VH439 (GY/VT) for a short together. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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P9 CHECK CIRCUITS LH111 (BN/WH) AND VH439 (GY/VT) FOR A SHORT TO GROUND
- Measure the resistance between ground and the following:
- HVAC module - EMTC C2357a-5, circuit LH111 (BN/WH), harness side.
- HVAC module - EMTC C2357a-18, circuit VH439 (GY/VT), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to P10.
No
REPAIR circuit(s) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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P10 CHECK CIRCUITS RH111 (GY/BU) AND VH439 (GY/VT) FOR A SHORT TO POWER
- Ignition ON.
- Measure the voltage between ground and the following:
- HVAC module - EMTC C2357a-15, circuit RH111 (GY/BU), harness side.
- HVAC module - EMTC C2357a-18, circuit VH439 (GY/VT), harness side.
- Is any voltage present?
Yes
REPAIR circuit(s) for a short to power. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to P11.
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P11 CHECK THE DOOR ACTUATOR OPERATION
NOTE: If a jumper fuse opens while carrying out this test step, repair the circuit(s) for a short.
- Measure the resistance between HVAC module - EMTC C2357a-15, circuit RH111 (GY/BU), harness side and HVAC module - EMTC C2357a-18, circuit VH439 (GY/VT), harness side.
- Connect a fused jumper wire between:
- HVAC module - EMTC C2357a-26, circuit SBP07 (WH/RD), harness side and HVAC module - EMTC C2357a-6, circuit CH234 (YE/GN), harness side.
- HVAC module - EMTC C2357a-1, circuit GD116 (BK/VT), harness side and HVAC module - EMTC C2357a-7, circuit CH233 (VT/BN), harness side.
- Remove the fused jumpers.
- Connect a fused jumper wire between:
- HVAC module - EMTC C2357a-26, circuit SBP07 (WH/RD), harness side and HVAC module - EMTC C2357a-7, circuit CH233 (VT/BN), harness side.
- HVAC module - EMTC C2357a-1, circuit GD116 (BK/VT), harness side and HVAC module - EMTC C2357a-6, circuit CH234 (YE/GN), harness side.
- Does the resistance smoothly increase and/or decrease when the jumpers are connected?
Yes
INSPECT for binding or broken door and linkage. If no condition is found, GO to P14.
No
GO to P12.
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P12 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS
- Measure the resistance between the HVAC module - EMTC C2357a-7, circuit CH233 (VT/BN), harness side and HVAC module - EMTC C2357a-6, circuit CH234 (YE/GN), harness side.
- Is the resistance between approximately 59-73 ohms?
Yes
INSPECT for binding or broken door and linkage. If no condition is found, INSTALL a new door actuator. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to P13.
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P13 CHECK THE ACTUATOR MOTOR DRIVE CIRCUITS FOR AN OPEN
NOTE: Due to limited connector accessibility, before carrying out this test step, visually inspect the wiring between the HVAC module and actuator for opens or shorts. If no damage is visually evident, proceed with the test.
- Disconnect: LH Blend Door Actuator C2091.
- Measure the resistance between the HVAC module - EMTC connector, harness side and LH blend door actuator, harness side using the following chart.
- Are the resistances less than 5 ohms?
Yes
INSTALL a new door actuator. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
REPAIR the circuit(s) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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P14 CHECK THE MODULE CONNECTION
- Carry out the HVAC Module Cold Boot Process. HVAC Module Cold Boot Process
- Operate the system.
- Does the concern return?
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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