Injection Control Pressure (ICP) Sensor

1997 PCED OBDII-Diesel

SECTION 5C: Pinpoint Tests

Z: Injection Control Pressure (ICP) Sensor

Z: Introduction

Z1 DIAGNOSTIC TROUBLE CODE (DTC) P1280: ICP CIRCUIT LOW INPUT

DTC P1280 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 between VREF Pin B and 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 between VREF Pin B and signal return Pin A.

Is voltage reading 5v ±0.5?

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.
Measure resistance between Pin 87 and 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

Measure resistance between Test Pin 90 and 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

Measure resistance between Test Pin 91 and 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 between Pin 87 and 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) P1281: ICP CIRCUIT HIGH INPUT: INDUCE OPPOSITE FAILURE

DTC P1281 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 P1280 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.
Measure resistance between Pin 87 and 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) P1212 OR P1210

DTC P1212 or P1210 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
damaged PCM

Key off.
Disconnect ICP sensor connector.
Measure resistance between signal return Circuit 359 (GY/R) pin A and 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 between ICP signal circuit pin C and ground.

Is voltage less than 0.25 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 kPa (0 psi)?

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

Z14 CONTINUOUS DIAGNOSTIC TROUBLE CODE (DTC) P1212

Note: This code may set after a high-pressure oil system repair (i.e., injector change). Drive vehicle to clear air from system after repair, and clear code.

Continuous DTC P1212 in federal vehicles, indicates that there was no ICP detected during crank (long crank time) or a bias ICP sensor signal was detected at key on.
On California vehicles, continuous DTC P1212 indicates that there was no ICP detected during crank (long crank time).
Possible causes:

high-pressure oil system repair
empty/low oil reservoir at crank
low engine oil level or incorrect viscosity
IPR circuit fault
damaged low-pressure oil pump
damaged IPR valve
damaged ICP sensor
damaged high-pressure oil pump

Check engine oil level.
Perform KOEO On-Demand Self Test to verify ICP/IPR circuit faults are not present at this time.

Are KOEO DTCs present?

Yes	No
SERVICE KOEO DTCs before continuing. If DTC P1212 returns. GO to Z15.	GO to Z15.

Z15 CHECK OIL RESERVOIR LEVEL

Note: If vehicle stalls after start and reservoir empties, oil is not being supplied from low pressure oil system.

Verify correct oil level, quality and viscosity.
Check oil level in oil reservoir.
Verify Steps 5 and 9 on the Hard Start/No Start Diagnostic Guide have been performed.
Install NGS Scan Tool.
Clear continuous memory DTCs.
Monitor ICP V PID on scan tool while cranking.

Is ICP V reading at least 0.85v within 5 seconds at crank?

Yes	No
DTC is intermittent. GO to Z19. If other DTCs are set, SERVICE them first.	GO to Z16.

Z16 CHECK ICP SENSOR

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.
Clear ICP DTCs.
Perform the Injection Control Pressure Leak Test per the procedures in Section 4C, Hard Start/No Start.

Is a leak fault indicated?

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

Z18 IPR 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) P1284

DTC P1284 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.

Z22 CONTINUOUS DIAGNOSTIC TROUBLE CODE P1210

Continuous DTC P1210 indicates ICP signal voltage was greater than expected with key on during normal driving conditions.
Possible causes:

biased ICP sensor
open ICP signal return circuit
ICP signal circuit shorted to power

Perform KOEO On-Demand Self Test.

Are KOEO ICP codes present?

Yes	No
SERVICE KOEO codes before continuing. If DTC P1210 is still present, GO to Z23.	DTC is intermittent. GO to Z23.

Z23 ICP SIGNAL GROUND CIRCUIT CHECK

ICP sensor disconnected.
Key on/engine off.
Measure resistance between signal return Circuit 359 (GY/R) Pin A and ground.
Observe resistance while performing the following.

Grasp the harness close to the sensor connector. Wiggle and shake vehicle harness while working toward the PCM.

Does resistance value stay below 5 ohms?

Yes	No
GO to Z24.	REPAIR intermittent open in Circuit 359 (GY/R). CLEAR DTCs and RETEST.

Z24 ICP SENSOR CIRCUIT CHECK

Key off.
Reconnect ICP sensor connector.
Clear ICP circuit code.
Key on.
Lightly tap ICP sensor.

Does code P1210 reappear?

Yes	No
REPLACE ICP sensor.	DTC is intermittent. Cannot duplicate failure at this time.