Circuit Description
The powertrain control module (PCM) uses the A/C relay to control the A/C compressor. With an A/C mode selected, the HVAC module sends a Class 2 message to the PCM. When the PCM receives the message, the PCM turns ON the A/C relay coil by grounding the A/C relay control circuit. This closes the relay contacts, and applies a fused battery voltage to the A/C compressor clutch coil. The PCM enables the compressor clutch whenever following conditions are present:
| • | Engine is running. |
| • | The PCM has received the A/C Request. |
| • | TP sensor indicates a throttle angle below 90 percent. |
| • | System voltage greater than 8 volts. |
| • | Engine speed is greater than 500 RPM. |
Diagnostic Aids
If the condition is intermittent, refer to Intermittent Conditions in Symptoms.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
2 | Is DTC P1545 set? | -- | Go to DTC P1545 Air Conditioning (A/C) Clutch Relay Control Circuit | |
3 | Is U1152 set? | -- | Go to Diagnostic System Check |
