Enabling Conditions And Possible Causes - Ambient Air Temp Sensor
| MONITORING CONDITIONS |
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| Circuit Low/High Faults - With the ignition on, battery voltage above a calibrated threshold. |
| Performance Fault - With the ignition on after an eight hour cold soak on the previous engine off cycle. Ambient Air, Intake Air, and Engine Coolant Temperature values are above -64°C (-83°F). |
| FAULT SETTING CRITERIA |
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| Circuit Low Fault - The sensor signal voltage is below a calibrated threshold. The threshold is typically in the 0.1 volt range. |
| Circuit High Fault - The sensor signal voltage is above a calibrated threshold. The threshold is typically in the 4.9 volt range. |
| Performance Fault - The sensor signal voltage is irrational - typically not within 10°C - 15°C (18°F - 27°F) of the other engine temp sensors. |
| POSSIBLE CAUSES |
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| TEMP SENSOR HARNESS CONNECTOR DAMAGED OR NOT CONNECTED COMPLETELY (CIRCUIT HIGH/PERFORMANCE FAULT) |
| TEMP SENSOR SIGNAL CIRCUIT SHORTED TO GROUND (CIRCUIT LOW FAULT) |
| TEMP SENSOR SIGNAL CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT (CIRCUIT LOW FAULT) |
| TEMP SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE (CIRCUIT HIGH FAULT) |
| TEMP SENSOR SIGNAL CIRCUIT OPEN/HIGH RESISTANCE (CIRCUIT HIGH/PERFORMANCE FAULT) |
| TEMP SENSOR RETURN CIRCUIT OPEN/HIGH RESISTANCE (CIRCUIT HIGH/PERFORMANCE FAULT) |
| FAULTY TEMP SENSOR (OPEN, SHORTED OR DRIFTED OUT OF RANGE) |
| FAULTY ELECTRONIC CONTROL UNIT (ECU) |