P1289 ICP Sensor Failure KOER Test
The P1289 code indicates a fault in the Injection Control Pressure (ICP) sensor during the Key On Engine Running (KOER) self-test. This test is performed with the engine running, and the code sets when the Powertrain Control Module (PCM) detects that the ICP sensor signal is outside expected parameters, causing the test to abort. The ICP sensor monitors oil pressure in the injection rail, which controls injection pressure and timing, making it critical for fuel injection system operation.
01. Most Common Causes
- Faulty ICP sensor
- Short or open circuit in ICP sensor wiring
- Poor electrical connection at the ICP sensor
- Low engine oil pressure
- Faulty PCM
02. Symptoms You Will Notice
- Engine may run rough or stall
- Check Engine Light illuminated
- Hard starting or no start
- Reduced engine power or performance
03. Step-by-Step Diagnosis
Scan for codes and verify P1289 is present
Inspect ICP sensor connector for damage, corrosion, or loose pins
Check ICP sensor wiring for shorts, opens, or chafing
Test ICP sensor signal voltage with a multimeter (typically 0.5-4.5V at idle)
Verify engine oil pressure is within specifications
If all else fails, test PCM or replace ICP sensor
1. Frequently Asked Questions
Is it safe to drive?▼
No, driving with this code is not recommended. The ICP sensor is critical for fuel injection control, and a failure can cause stalling, poor performance, or engine damage. Have the vehicle diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs typically range from $150 to $500, depending on the cause. A new ICP sensor costs $50-$150, plus labor. Wiring repairs or PCM replacement can increase the cost.