A/C On During KOER CCT Test
The P1464 code indicates that during the Key On Engine Running (KOER) Cylinder Contribution Test (CCT), the Air Conditioning (A/C) system was detected as being on. This test requires the A/C to be off to accurately measure cylinder contribution. The code is typically set when the PCM detects the A/C clutch or compressor is engaged during the test, which can skew results and prevent the test from completing properly.
01. Most Common Causes
- A/C switch left on during KOER test
- Faulty A/C clutch relay stuck closed
- Short circuit in A/C control circuit
- PCM software issue or incorrect test procedure
02. Symptoms You Will Notice
- KOER test fails or aborts
- Check Engine Light illuminated
- A/C may run continuously or not turn off
03. Step-by-Step Diagnosis
Step 1: Ensure A/C is off and retest KOER
Step 2: Check A/C clutch relay for stuck closed condition
Step 3: Inspect wiring and connectors for shorts to power
Step 4: Verify PCM operation and update software if needed
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but the KOER test will not complete, and the Check Engine Light may stay on. The A/C may also operate unexpectedly.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and repair, often just turning off the A/C or replacing a relay.