DTC 67

DTC 67 Chart:

A/C Circuit:

Circuit Description:
The PCM can determine if the A/C compressor clutch is engaged or not engaged through the A/C clutch status line. If the PCM has grounded the coil of the A/C clutch control relay, current can flow through the relay contacts to the A/C compressor clutch and the PCM on the A/C status circuit.

When voltage is present at the PCM A/C clutch status terminal, A/C status "ON" will be displayed on the Tech 1. As the PCM detects that the A/C compressor clutch has cycled "OFF" (through the A/C control switch etc.), the PCM will record A/C system pressure from the A/C refrigerant pressure sensor. If the A/C refrigerant pressure does not increase more than 9 psi when the A/C clutch is turned back "ON," a DTC 67 will set. This condition can occur if the A/C refrigerant pressure sensor is fixed at one value, or if the A/C refrigerant pressure sensor ground is open.

DTC 67 Will Set When:
The PCM does not detect an A/C refrigerant pressure change of more than 9 psi when the A/C clutch has been cycled.

Action Taken (PCM Will default to):
The MIL will not become illuminated. The A/C compressor will become disabled, the cooling fan will not be enabled unless A/C had been requested first and the vehicle speed is above 35 mph with a current DTC 67.

DTC 67 Will Clear When:
A current DTC 67 will clear when the A/C pressure signal shows an increase of more than 9 psi since the last time the A/C clutch has been cycled. A history DTC 67 will clear after 50 consecutive ignition key cycles without a current DTC 67 being stored.

Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.

1. Checks to see if the PCM detects an A/C refrigerant pressure range of more than 9 psi when the A/C clutch has been cycled.

2. If the rela power feed CKT 139 is intermittent, the A/C clutch status terminal may not detect voltage when A/C is commanded "ON."

3. If the A/C clutch status line becomes intermittently open or shorted while the compressor is "ON," the PCM will be wrongly detecting the A/C clutch going "ON" and "OFF." When the PCM falsely detects the clutch cycling from "ON" to "OFF" and the clutch is remaining "ON," a DTC 67 will set since no pressure change was detected.

4. If the A/C compressor clutch is disconnected or if CKT 59 is open between the splice and the clutch, the A/C compressor clutch will not engage, but the PCM will detect voltage on the A/C status line which will indicate the clutch is "ON." If the A/C controls are cycled from "OFF" to "ON" at this point, a DTC 67 will set since the clutch did not engage and therefore no pressure change was detected.

5. The remaining tests check the A/C refrigerant pressure sensor circuit for proper operation.

Diagnostic Aids:
A DTC 67 will store in PCM memory but will not turn "ON" the Malfunction Indicator Lamp (MIL) "Service Engine Soon."