Diagnostic Aids
WARNING: This page is about a different variant/trim than selected.
NOTE:
After each service or repair procedure has been completed, reconnect all components. Clear DTCs and repeat QUICK TEST procedures to ensure all electronic engine control systems are working properly and DTCs are no longer present.
Perform this test when directed by QUICK TEST. This test is only intended to diagnose the following components and circuits:
- Injection Pressure Regulator (IPR)
- Injection Control Pressure (ICP) Sensor
- Powertrain Control Module (PCM)
- Wiring harness circuit (IPR)
- Output Functions
Injection Pressure Regulator (IPR) is a variable position valve that controls injection control pressure. PCM uses many input variables to determine desired injection control pressure. Battery voltage is supplied to IPR when ignition is on. Valve position is controlled by switching output signal circuit to ground inside PCM. ON/OFF time is modulated from 0-50 percent, dependent upon desired injection control pressure. - Detection & Management
An open or shorted to ground control circuit can be detected during KOEO ON-DEMAND SELF-TEST. When starter is engaged and engine fails to start, IPR command will increase toward its maximum until engine starts. Normal range for IPR at idle is between 8-16 percent. A range above 16 percent indicates high effort to achieve idle. A range below 8 percent indicates low effort to achieve idle. PCM is capable of detecting whether desired injection control pressure is equal to measured injection control pressure while engine is running. If measured injection control pressure does not reasonably compare to desired injection control pressure, PCM ignores measured ICP sensor signal and attempts to control engine with desired value. If problem is in sensor circuit, this strategy causes little performance deterioration. If problem is in control circuit, engine performance will probably still be unsatisfactory. An injection control pressure step test, in which PCM commands and then measures specific preprogrammed pressures is performed during KOER ON-DEMAND SELF-TEST.
NOTE:
The engine will not operate with an IPR circuit that is not functioning.