Circuit Description
The air temperature valve sensor and motor is driven by the electronic climate control (ECC) module in order to operate the air mix door. The position of the air temperature valve is adjusted in order to maintain the verified air-outlet temperature. A feedback potentiometer is used in the flat-pack motor so that the ECC module will know the position of the air temperature valve. A low voltage at CKT 733 (about 1.0 volt) represents a cold air temperature valve position and a high voltage on CKT 733 (about 4.0 volts) represents a hot air temperature valve position. The ECC module drives the air temperature valve sensor and motor through CKT 1199 to the logic portion of the air temperature valve sensor and motor by applying 0 volts, 2.5 volts, and 5 volts through this circuit. Applying 5.0 volts on CKT 1199 to the logic portion of the air temperature valve sensor and motor will cause the air temperature valve to move to the FULL COLD position. Applying 0.0 volts on CKT 1199 to the logic portion of the air temperature valve sensor and motor will cause the air temperature valve to move to the FULL HOT position. Applying approximately 2.5 volts on CKT 1199 will cause the air temperature valve sensor and motor to stop.
Conditions for Setting the DTC
With the ignition ON, the ECC module will detect DTC B0416 anytime that CKT 733 is near 5 volts or higher.
Action Taken When the DTC Sets
The ECC module will drive the air temperature valve to the FULL COLD position if the system is in one of the following modes:
| • | UPPER OUTLET |
| • | BI-LEVEL |
| • | AUTO UPPER OUTLET/BI-LEVEL |
The ECC module will drive the air temperature valve to the full heat position if the system is in one of the following modes:
| • | LOWER |
| • | DEFOG |
| • | DEFROST |
| • | AUTO LOWER |
Conditions for Clearing the MIL/DTC
DTC B0416 will clear as soon as the fault goes away or has been repaired. The system will then return to normal operation. History DTCs may only be cleared by removing and restoring B+ or by using the scan tool.
Diagnostic Aids
| • | The ECC module may set class 2 lost communication DTCs when the body control module (BCM) or the vehicle control module (VCM) is being reprogrammed. After reprogramming, inspect for DTCs in the ECC module. Clear any history U DTCs then resume diagnostics. |
| • | Visually inspect the air temperature valve sensor and motor and harness connector for loose or bent pins. If B+ has been removed from the ECC module and then restored for any reason, the ECC module system will (one time) drive the air temperature valve to the FULL HOT position and then to the FULL COLD position when power is restored. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step inspects for a short to B+ on CKT 733 and CKT 1688.
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This step determines if a short to B+ is in the ECC module and wiring or the air temperature valve sensor and motor.
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This step isolates the short to B+ to either the wiring or the ECC module.
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This step repairs the short to B+ in CKT 1688 and CKT 733.
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This step inspects for an open in CKT 733 and CKT 1688.
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This step determines if the open is in CKT 733 and CKT 1688 or the ECC module.
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This step inspects for an open in CKT 1791.
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This step inspects for a defective air temperature valve sensor and motor by temporarily installing a known good air temperature valve sensor and motor.
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This step replaces the defective air temperature valve sensor and motor.
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This step determines if the open is in CKT 1791 or in the ECC module.
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This step replaces a defective ECC module.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check |
Is the voltage within the specified range? | 9-16 V | Go to Step 3 | Go to Step 6 | |
Is the voltage within the specified range? | 9-16 V | Go to Step 4 | Go to Step 11 | |
Is battery voltage present in any circuit? | -- | Go to Step 5 | Go to Step 14 | |
Repair the short to B+ in CKT 733 and CKT 1688. Is the repair complete? | -- | Go to Diagnostic System Check | -- | |
Does the voltage equal the specified value? | 5 V | Go to Step 9 | Go to Step 7 | |
Inspect for an open in CKT 733 and CKT 1688. Did you find an open? | -- | Go to Step 8 | Go to Step 14 | |
8 | Repair the open in CKT 733 and/or CKT 1688. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
Test for continuity to ground at terminal 7 of the air temperature valve sensor and motor harness connector. Is an open circuit present? | -- | Go to Step 12 | Go to Step 10 | |
Does the test air temperature valve sensor and motor function normally while changing temperatures? | -- | Go to Step 11 | Go to Step 14 | |
Replace the air temperature valve sensor and motor. Refer to Temperature Actuator Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | -- | |
Inspect for an open in CKT 1791 (YEL) (including the ECC module). Did you find an open? | -- | Go to Step 13 | Go to Step 14 | |
13 | Repair the open in CKT 1791 (YEL). Is the repair complete? | -- | Go to Diagnostic System Check | -- |
Replace the ECC module. Refer to Control Assembly Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | -- |
