Circuit Description
A voltage is supplied directly to the A/C compressor clutch relay coil. The PCM controls the relay by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the controlled component. Each driver has a fault line which the PCM monitors. When the PCM commands a component ON, the voltage of the control circuit should be low (near 0 volts). When the PCM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high (near battery voltage). If the fault detection circuit senses a voltage other than what the circuit expects, the fault line status changes causing the DTC to set.
Conditions for Setting the DTC
| • | The engine speed is greater than 400 RPM. |
| • | The ignition voltage is greater than 6 volts but less than 18 volts. |
Conditions for Running the DTC
| • | The PCM detects that the commanded state of the driver and the actual state of the control circuit do not match. |
| • | Condition must exist for a minimum of 5.0 seconds. |
Action Taken When the DTC Sets
| • | The PCM stores the DTC information into memory when the diagnostic runs and fails. |
| • | The Malfunction Indicator Lamp (MIL) will not illuminate. |
| • | The PCM disables the A/C. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A last test failed (current DTC) clears when the diagnostic runs and does not fail. |
| • | A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. |
| • | Use a scan tool in order to clear the MIL/DTC. |
Diagnostic Aids
Important:
• Remove any debris from the PCM\TAC module connector surfaces before
servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets
when diagnosing/replacing the modules. Ensure that the gaskets are installed
correctly. The gaskets prevent contaminate intrusion into the PCM\TAC
modules. • For any test that requires probing the PCM or a component
harness connector, use the Connector Test Adapter Kit J 35616
. Using this kit prevents damage
to the harness/component terminals. Refer to
Using Connector Test Adapters
in Wiring Systems.
A/C Clutch Relay Underhood Electrical Center Terminal Identification | |||
|---|---|---|---|
Front of Vehicle | |||
Left Side of Vehicle | Ignition | Load | Right Side of Vehicle |
Ignition | Control | ||
| • | If the A/C minifuse is open, inspect for a short to ground on the A/C Compressor Clutch circuit and/or the A/C Clutch status circuit. |
| • | Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed. |
| • | For an intermittent condition, refer to Symptoms . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Listen for an audible click when the relay operates. Command both the ON and the OFF states as necessary.
-
Energize the relay for 2 minutes in order to detect excessive current flow . Energizing the relay for 2 minutes warms the relay coil. When the relay is warm the coil may open (the current draw drops to 0), or short (the current goes above 0.75 Amps).
-
It is important to identify and test the relay coil terminals to avoid improper diagnosis.
-
Listen for an audible click when the relay operates. Ground the circuit as necessary.
-
If the fuse is open, inspect the relay load circuit for a short to ground.
-
If no trouble is found in the control circuit or the connection at the PCM, the PCM may be faulty, however, this is an extremely unlikely failure.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the relay turn ON and OFF when commanded? | -- | |||
Important: If the DMM displays 0 during the current draw test replace the relay. Does the current draw measure less than the value? | 0.75A | Go to Diagnostic Aids | ||
4 |
Does the DMM display infinite resistance? | -- | ||
Does the test lamp turn ON and OFF with each command? | -- | |||
6 | Probe the A/C Clutch relay ignition feed circuits in the underhood electrical center with the test lamp J 35616-200 connected to a ground. For terminal identification refer to Diagnostic Aids. Does the test lamp illuminate for both circuits? | -- | ||
Does the relay turn ON when the control circuit is grounded and turn OFF when the circuit is opened? | -- | |||
8 |
Did you find and correct the condition? | -- | ||
9 |
Did you find and correct the condition? | -- | ||
10 | Repair the faulty relay control circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
Repair the faulty relay ignition feed circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | ||
12 | Replace the relay. Is the action complete? | -- | -- | |
|
Important:: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | -- | ||
14 |
Does the scan tool indicate that this test failed? | -- | ||
15 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
