Injection Control Pressure (ICP) Sensor

1996 PCED OBDI

SECTION 18: Diesel Diagnosis — 7.3L DI Engine

Z: Injection Control Pressure (ICP) Sensor

Z: Introduction

Z1 DIAGNOSTIC TROUBLE CODE (DTC) 1280: ICP CIRCUIT LOW INPUT

DTC 1280 indicates injector control signal circuit out of range low was detected during KOEO Self Test or during continuous diagnostic monitoring.
Possible causes:

Biased ICP sensor/PCM
Open ICP sensor circuit
Short to SIG RTN or PWR GND on ICP sensor circuit
Open in VREF circuit

Disconnect ICP sensor connector.
Key on/engine off.
Measure voltage at VREF Pin B to battery ground.

Is voltage reading 5v ±.5?

Yes	No
GO to Z2.	REPAIR open in VREF Circuit 351 (BR/W). CLEAR DTCs and RETEST.

Z2 SIGNAL RETURN CIRCUIT CHECK

Measure voltage from VREF Pin B to signal return Pin A.

Is voltage reading 5v ±.5?

Yes	No
GO to Z3.	REPAIR open in signal return Circuit 359 (GY/R). CLEAR DTCs and RETEST.

Z3 ICP SIGNAL CIRCUIT CHECK

Key off.
Disconnect PCM. Inspect for loose, damaged or pushed-out pins. Repair as necessary.
Connect breakout box. PCM disconnected.
Check resistance from Pin 87 to Pin C at ICP sensor harness connector.

Is resistance less than 5 ohms?

Yes	No
GO to Z4.	REPAIR open in signal Circuit 812 (DB/LG) for F-Series or 535 (LB/R) for Econoline. CLEAR DTCs and RETEST.

Z4 VREF CIRCUIT CHECK

Check resistance from Test Pin 90 to Pin B at ICP sensor harness connector.

Is resistance less than 5 ohms?

Yes	No
GO to Z5.	REPAIR open in VREF Circuit 351 (BR/W). CLEAR codes and RETEST.

Z5 SIGRTN CIRCUIT CHECK

Check resistance from Test Pin 91 to Pin A at ICP sensor harness connector.

Is resistance less than 5 ohms?

Yes	No
GO to Z6.	REPAIR open in SIG RTN Circuit 359 (GY/R). CLEAR codes and RETEST.

Z6 SENSOR SIGNAL CIRCUIT SHORT TO GROUND

Measure resistance from Pin 87 to Pins 25/51/76/77/91/103.

Is resistance greater than 10,000 ohms?

Yes	No
GO to Z7.	REPAIR short to ground in signal wire Circuit 812 (DB/LG) for F-Series or 535 (LB/R) for Econoline. CLEAR DTCs and RETEST.

Z7 CHECK FOR SHORT ON PIN 87

Connect breakout box to PCM.
Measure resistance between Pin 87 and Pins 25/91/51/76/77 and 103.

Is resistance greater than 10,000 ohms?

Yes	No
REPLACE ICP sensor. RERUN Scan Tool Diagnostic Test.	REPLACE PCM. REMOVE breakout box. RECONNECT ICP sensor. RERUN Scan Tool Diagnostic Test.

Z8 DIAGNOSTIC TROUBLE CODE (DTC) 1281: ICP CIRCUIT HIGH INPUT: INDUCE OPPOSITE FAILURE

DTC 1281 indicates injector control pressure circuit out of range high during KOEO Self Test or during continuous diagnostic monitoring.
Possible causes:

Biased ICP sensor/PCM
ICP circuit shorted to VREF

Key on/engine off.
Disconnect ICP harness connector.
Check DTCs.

Does DTC 1280 appear?

Yes	No
REPLACE ICP sensor. CLEAR DTCs and RETEST.	GO to Z9.

Z9 CHECK FOR SHORT TO POWER

Disconnect PCM. Inspect for damaged, corroded, loose or pushed-out wires. Repair as necessary.
Install breakout box. PCM disconnected.
Check resistance from Pin 87 to 55/71/90/97.

Is resistance greater than 10,000 ohms?

Yes	No
GO to Z10.	REPAIR short to power in signal Circuit 812 (DB/LG) for F-Series or 535 (LB/R) for Econoline. CLEAR DTCs and RETEST.

Z10 CHECK FOR SHORT ON PIN 87

Connect breakout box to PCM.
Measure resistance between Pin 87 and Pins 55/71/90/97.

Is resistance greater than 10,000 ohms?

Yes	No
REPLACE ICP sensor. CLEAR DTCs and RETEST.	REPLACE PCM. REMOVE breakout box. CLEAR DTCs and RETEST.

Z11 KOEO DIAGNOSTIC TROUBLE CODE (DTC) 1212

DTC 1212 indicates ICP signal voltage was greater than expected during KOEO On-Demand Self Test.
Possible causes:

Biased ICP sensor
Open ICP signal return
Signal circuit shorted to power
Faulty PCM

Key off.
Disconnect ICP sensor connector.
Measure resistance from signal return Circuit 359 (GY/R) pin A to ground.

Is resistance less than 5 ohms?

Yes	No
GO to Z12.	REPAIR open in signal return Circuit 359 (GY/R). CLEAR DTCs and RETEST.

Z12 CHECK SIGNAL CIRCUIT SHORT TO POWER

ICP sensor disconnected.
Key on/engine off.
Measure voltage from ICP signal circuit pin C to ground.

Is voltage less than .25 volts?

Yes	No
GO to Z13.	REPAIR short to power in ICP signal circuit. CLEAR DTCs and RETEST.

Z13 ICP SENSOR CHECK

Key off.
Reconnect ICP sensor connector.
NGS Tester installed.
Key on/engine off.
Access ICP PID from the PID/DATA monitor menu on the NGS Tester.

Is ICP reading 0 PSI?

Yes	No
REPLACE PCM. CLEAR DTCs and RETEST.	REPLACE ICP sensor. CLEAR DTCs and RETEST.

Z14 CONTINUOUS DIAGNOSTIC TROUBLE CODE (DTC) 1212

Continuous DTC 1212 indicates there was no ICP signal voltage present during cranking.
Possible causes:

Empty/low oil reservoir
IPR circuit fault
Faulty IPR valve
Faulty ICP sensor
Faulty high pressure pump

Perform KOEO On-Demand Self Test.

Are KOEO DTCs present?

Yes	No
SERVICE KOEO DTCs before continuing. If DTC 1212 is still present, GO to Z15.	If vehicle starts, the DTC is intermittent. GO to Z19. If vehicle does not start, GO to Z15.

Z15 CHECK OIL RESERVOIR LEVEL

Check oil level in oil reservoir.
Verify correct oil quality and viscosity.

Is oil level and quality OK?

Yes	No
GO to Z16.	FILL oil reservoir. CLEAR DTCs. If vehicle does not start, GO to Z16.

Z16 ICP SENSOR CHECK

Disconnect ICP sensor connector.

Does vehicle start?

Yes	No
REPLACE ICP sensor. CLEAR DTCs and RETEST.	GO to Z17.

Z17 HIGH PRESSURE LEAKAGE TEST

Reconnect ICP sensor connector.
Perform the Injection Control Pressure Leak Test per the procedures in the Hard Start/No Start section (Step 9C).

Is a leak fault indicated?

Yes	No
REPAIR condition causing the leak as necessary. CLEAR DTCs.	GO to Z18.

Z18 IPS VALVE CHECK

Reconnect all hoses and ICP sensor.
Replace IPR valve.
Refill oil reservoir.

Does vehicle start?

Yes	No
IPR valve was faulty. CLEAR DTCs.	REPLACE the high pressure pump. CLEAR DTCs.

Z19 CHECK FOR INTERMITTENT CIRCUIT FAULTS

Key on/engine off.
Access ICP PID from the PID/DATA monitor menu on the NGS Tester.
Grasp the vehicle harness close to the sensor connector. Wiggle, shake vehicle harness while working towards the PCM.

Does ICP reading fluctuate?

Yes	No
REPAIR circuit as required. CLEAR DTCs and RETEST.	GO to Z20.

Z20 INSPECT IPR CIRCUIT

Inspect IPR circuit from IPR valve through 42-way connector to the PCM.

Are any faults indicated?

Yes	No
REPAIR circuit as required. CLEAR DTCs and RETEST.	Unable to verify concern at this time. CLEAR DTCs and RETEST.

Z21 DIAGNOSTIC TROUBLE CODE (DTC) 1284

DTC 1284 indicates that a ICP circuit failure was present while trying to perform KOER Cylinder Contribution Self Test.
Perform KOEO On-Demand Self Test.

Is a ICP circuit fault indicated?

Yes	No
REFER to appropriate Pinpoint Test for ICP DTC retrieved.	REPLACE PCM. CLEAR DTCs and RETEST.