B0186

Circuit Description

The solar load sensor is a reverse bias photo diode that measures sun load on the vehicle. The sensor is an input to the heater and A/C control module. High sensor impedance equates to full darkness. Low sensor impedance equates to bright sunlight.

Conditions for Setting the DTC

With the ignition ON, the heater and A/C control module will detect DTC B0186 any time that CKT 590 is at or near 5 volts or higher.

Action Taken When the DTC Sets

The heater and A/C control module will use a default value of approximately 200 A/D counts until the fault is cleared.

Conditions for Clearing the MIL/DTC

This fault will clear as soon as the fault goes away or has been repaired. The system will then return to normal operation. History DTCs can only be cleared by removing and restoring B+ or by using the scan tool.

Diagnostic Aids

- The heater and A/C control module may set class 2 lost communication DTCs when the Body Control Module (BCM) or the VCM is being reprogrammed. After reprogramming, inspect for DTCs in the heater and A/C control module. Clear any history U DTCs, then resume diagnostics.
- Visually inspect the sensor connector and harness for corrosion and damage.

Test Description

The numbers below refer to the step numbers of the diagnostic table.

1. This step inspects to a short to B+ on CKT 590.
2. This step determines is the short to B+ is 110 CKT 590 or in the heater and A/C control module.
3. This step inspects for an open in CKT 552.
4. This step reads solar load sensor counts.
5. This step replaces defective solar load sensor in # 1.
6. This step repairs an open in CKT 552.
7. This step inspects for Intermittents and tests for a malfunctioning heater arid A/C control module.
8. This step replaces a defective heater arid A/C control module.
9. This step inspects for 5 volts or CKT 590.
10. This step determines if the open is in CKT 590 or In the heater and A/C control module.