Injection Control Pressure (ICP) Tests

TEST A. - Oil Aeration






PURPOSE
To determine if the engine lube oil is aerated and causing poor idle quality.

RECOMMENDED PROCEDURE
Install the Breakout Box on the Powertrain Control Module (PCM). Measure the Injection Control Pressure (ICP) signal through Pins 87 and 91. Make sure the parking brake is on and the transmission is out of gear. Operate the engine at high idle (WOT) for 60 seconds while monitoring the ICP signal. A normal signal is between 1.1 and 2.0 volts. If the signal does not stabilize below 2.0 volts and continues to rise as high idle speed is maintained, the engine lube oil may be aerated. Change oil and filter and retest.

POSSIBLE CAUSES
- Extended oil drain intervals. The anti-foam additives in the oil may be depleted either from severe use or extend drain intervals.
- Wrong type or grade oil

TOOLS REQUIRED
Rotunda DVOM 105-00050, Rotunda 104 Pin Breakout Box 014-00950

TEST B. - Idle Stability/Low Power Condition






PURPOSE
To determine if idle stability and/or low power is caused by a stuck or dirty Injection Pressure Regulator (IPR) or bad ICP signal.

RECOMMENDED PROCEDURE
Install the Breakout Box on the PCM. Measure the ICP signal through Pins 81 and 91. Make sure the parking brake is on and the transmission is out of gear. Operate the engine at low idle (650 rpm). A normal signal with the engine at operating temperature is between 0.7 and 1.0 volts. If the signal and engine does not stabilize, disconnect the ICP sensor. If the low idle speed stabilizes with the ICP sensor disconnected the problem is most likely in the ICP sensor circuit. X - Injection Pressure Regulator (IPR)

If the rpm does not stabilize, change the IPR valve and retest.

POSSIBLE CAUSES
- Debris stuck in the IPR valve (not serviceable)
- In-range ICP sensor or circuit failure
- PCM failure

TOOLS REQUIRED
Rotunda DVOM 105-00050, jumper harness/probe or a Rotunda 104 Pin Breakout Box 014-00950