Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ignition Voltage | 1 | 1 | -- | -- |
Outside Moisture Sensor Signal 1 | 1 | 1 | 1 | -- |
Outside Moisture Sensor Signal 2 | 1 | 1 | 1 | -- |
Ground | -- | 1 | -- | -- |
1. Moisture sensing feature is inoperative | ||||
Circuit/System Description
Ignition voltage is supplied to the outside moisture sensor from the body control module (BCM). Whenever the ignition is in the run or accessory positions, the BCM sends the wiper/washer switch status using a pulse width modulated (PWM) signal through the outside moisture sensor signal 1 circuit to the outside moisture sensor. When a wipe cycle is needed, the moisture sensor sends a PWM voltage signal through the moisture sensor signal 2 circuit back to the BCM requesting the wiper operation.
The outside moisture sensor uses the moisture sensor signal 2 circuit to command wiper motor wipe cycles and to confirm the moisture sensor signal 1 is being received. If at anytime a fault occurs between the outside moisture sensor and BCM, the BCM will use the inputs from the windshield wiper/washer switch in the delay positions to operate the wiper motor at continuous variable delay intervals.
Diagnostic Aids
Inspect the silicon gel linking the sensor to the windshield for any distortion, or blockage of the sensor lens.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, wiper switch in the low position. The windshield wipers should operate at low speed. If the windshield wipers do not operate, refer to Windshield Wiper System Malfunction.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the outside moisture sensor.
- Test for less than 5.0 ohms between the ground circuit terminal 3 and ground.
- Ignition ON, verify that a test lamp illuminates between ignition circuit terminal 4 and ground.
- Ignition OFF, connect the harness connector at the outside moisture sensor.
- Disconnect the X4 harness connector at the BCM.
- Ignition ON, test for 8-10 volts between the signal circuit terminal 18 and ground.
- Ignition ON, test for 4-8.5 volts between the signal circuit terminal 14 and ground.
- If all circuits test normal, replace the BCM.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the outside moisture sensor. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the outside moisture sensor. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the outside moisture sensor. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the outside moisture sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
