P2181

P2181 - Cooling System Performance






For wiring diagrams, refer to.

• When Monitored: With the engine running and no engine coolant temperature sensor DTCs present.

• Set Condition: The ECT sensor voltage should only change at a certain rate. If this rate is too slow or too fast, this fault will set. Two trip fault. Three good trips to clear MIL. ETC light will illuminate on first trip failure.






• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure

Test Step 1 - Active DTC

• Improper installation of a block heater could cause this DTC to set.

• Review freeze frame data. Extremely cold ambient temperatures may cause this DTC to set.

• Diagnose and repair any ECT sensor circuit or temperature sensor performance DTCs before continuing with this test.

• Inspect the cooling system for any conditions that can cause a change in engine warm up time, such as a broken water pump impeller or the addition of an aftermarket auxiliary cooler.

• Turn the ignition ON.

• With the scan tool, select view DTCs.

Is the status active for this DTC?

Yes

• Go to Test Step 2 => [ Test
Step 2 - Checking the Engine Coolant Temperature Sensor Operation ]

No

• Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC

Test Step 2 - Checking the Engine Coolant Temperature Sensor Operation

• Perform the diagnostic procedure for Checking the Engine Coolant Temperature Sensor Operation. Refer to => Non-DTC Based Diagnostics. Engine Coolant Temperature Sensor Operation Test

Were any problems found?

Yes

• Repair as necessary.

• Perform the Powertrain Verification Test. Refer to => Non-DTC Based Diagnostics. PCM Verification Test

No

• Perform the Powertrain Verification Test. Refer to => Non-DTC Based Diagnostics. PCM Verification Test