Powertrain Controls - ECM/PCM

Diagnostic Trouble Code (DTC) 61:

Dtc 61:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) monitors A/C refrigerant pressure and A/C evaporator temperature to determine if the A/C system has adequate refrigerant (R134a) charge. The PCM will disable the A/C clutch whenever A/C refrigerant charge drops below a predetermined value, to reduce the chance of compressor damage. The PCM will cycle the compressor more frequently if the charge is only slightly low.

The PCM determines A/C charge based on A/C refrigerant pressure and A/C evaporator temperature. The PCM uses these two inputs to calculate A/C refrigerant charge.

DIAGNOSTIC TROUBLE CODE (DTC) 61 Will Set When
The PCM calculates refrigerant charge to be below a predetermined level.

ACTION TAKEN (PCM WILL DEFAULT TO)
If the PCM determines A/C refrigerant charge to be low, the A/C clutch will be disabled and DTC 61 will be set. DTC 61 will be stored in the PCM memory, but will not turn "ON" the Malfunction Indicator lamp (MIL).

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. DTC 61 could be caused by other DTCs, so refer to those charts before proceeding with this diagnostic chart.
2. If the A/C refrigerant pressure sensor is "skewed" or "shifted" in value, the PCM could be detecting a lower than normal pressure. Therefore, the PCM would be sensing a low refrigerant change and DTC 61 could result.
3. The conditions to set a DTC 67 could cause DTC 61 to set. DTC 67 will set if the PCM does not detect an A/C refrigerant pressure change of more than 4 psi when the A/C clutch is cycled from "OFF' to "ON."
4. The A/C performance test must be performed, because A/C system hardware (A/C compressor, thermal expansion valve etc.) could cause a DTC 61.

DIAGNOSTIC AIDS
An A/C evaporator temperature sensor and/or an A/C refrigerant pressure sensor that is "skewed" (shifted in value) could cause a DTC 61.