this is to test the icp sensor
Injection Control Pressure (ICP) Sensor Voltage Checks (check with key-ON engine-OFF)
Install the 3 wire breakout tee between the ICP sensor and harness connector. View ICP VOLTAGE using the Continuous Monitor test found under the diagnostics menu in MASTER DIAGNOSTICS. If the circuit has an active fault according to the voltage level (Code124 <0.039V, Code 125 >4.9V, Code 332 >1.625V), complete the following steps. Tests must be performed in order.
If voltage >0.039V, check signal circuit for short to V REF or B+.
Measure voltage from PIN B to gnd using a DMM.
5V ± 0.5
If voltage is >5.5V, check V REF for short to B+. If voltage is <4.5V, check V REF for open or short to Ground.
0.5 kΩ jumper installed between the GREEN and BLUE pins of the breakout tee.
If voltage is <4.9V, check signal circuit for open circuit or short to ground. Remove positive battery cable. Measure resistance from PIN C to Ground (spec >500Ω) and from PIN C to PIN 16 (spec <5Ω) using a breakout box to determine if short to ground or open is in the harness.
Standard jumper installed between the BLUE, GREEN, and BLACK pins of the breakout tee.
If voltage is >0.039V, check ground circuit for resistance. Measure resistance between PIN A and PIN 19 (spec <5Ω) using a breakout box to determine if resistance is in the harness.
Replace the sensor if the code is active and the expected results are obtained with all the sensor tests. The sensor is not at fault if one or more of the sensor tests does not produce the expected results. See ICP Sensor Troubleshooting Flowchart .
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OPERATIONAL VOLTAGE CHECKS
MD Voltage: Signal (GREEN tee) to gnd
Check with breakout tee installed, key ON
0.15 to 0.3V
Atmospheric pressure with key-ON engine-OFF
Minimum at engine cranking speed
0.74 - 0.81V
425 - 475
Normal warm low idle
Diagnostic Trouble Code Description
124 = Signal voltage was <0.039 volts for more than 1.0 sec.
125 = Signal voltage was >4.9 volts for more than 1.0 sec.
332 = Signal voltage was >1.625 volts, ignition key ON, engine OFF (1160 psi).
ICP Sensor Circuit Specifications
CONNECTOR VOLTAGE CHECKS (check with sensor disconnected from harness, key ON)
A to gnd
Signal ground, no voltage expected
B to gnd
If voltage not in spec., Vref circuit shorted to gnd or B+
C to gnd
If voltage > spec., wire shorted to Vref or B+
CONNECTOR CHECKS TO CHASSIS GROUND (check with sensor connector disconnected, positive battery cable disconnected, and key OFF)
A to gnd
> 5Ω, indicates circuit is open
B to gnd
< 500Ω, indicates short to ground
C to gnd
< 1kΩ, indicates short to ground
HARNESS RESISTANCE CHECKS (check with breakout box installed on chassis side only)
19 to A
If >5Ω indicates ground wire open
40 to B
If >5Ω indicates V REF wire open
16 to C
If >5Ω indicates signal wire open
The International engine control system includes an Injection Control Pressure Sensor. The ECM measures the signal from the ICP sensor to determine the Injection Control Pressure as the engine is running to modulate the Injection Control Pressure Regulator. This is a closed loop function which means the ECM continuously monitors and adjusts for ideal Injection Control Pressure which is determined by operating conditions such as load, speed, and temperature.
The ECM monitors the ICP signal to determine if the performance of the hydraulic system is satisfactory. During engine operation, if the ECM recognizes that the pressure reading is lower or higher than the value that was commanded, the ECM will set a Diagnostic Trouble Code. This strategy is also used during the On Demand tests, commanded by the EST and referred to as the Engine Running tests.
The Injection Control Pressure Sensor is a variable capacitance sensor that is supplied with a 5V reference voltage at terminal B from ECM terminal 40. The ICP sensor is also supplied with a return circuit (ground) at terminal A from ECM terminal 19. The ICP sensor sends a signal from terminal C of the sensor to ECM terminal 16.
The ICP signal voltage changes in direct proportion to the injection control pressure.
The ECM continuously monitors the voltage signal of the ICP sensor to determine if the signal is within an expected range. If the signal voltage is higher or lower than expected, the ECM will set a Diagnostic Trouble Code. The ECM will then ignore the ICP sensor signal and will use a preset value determined by engine operating conditions. If the ignition key is shut off, the code will become inactive.
ICP Diagnostic Trouble Codes can be retrieved using the Electronic Service Tool (EST) or by reading the Diagnostic Trouble Code flashes from the amber and red ENGINE lamps, see .
If the ignition key is shut off, the code will become inactive. ICP codes will cause the ECM to illuminate the amber ENGINE lamp and the odometer to display the message WARN ENG.
Diagnostic Trouble Code 124
ATA Code, PID 164, FMI 4
ICP signal Out of Range LOW
When code 124 is active the amber ENGINE lamp is illuminated and the odometer displays the message WARN ENG.
An Out of Range LOW code 124 will be set by the ECM if the signal voltage is less than 0.039V for more than 1.0 seconds.
Diagnostic Trouble Code 124 may be set due to an open or short to ground on the signal circuit, a defective sensor or an open V REF circuit.
Diagnostic Trouble Code 125
ATA Code, PID 164, FMI 3
ICP Signal Out Of Range HIGH
When code 125 is active the amber ENGINE lamp is illuminated and the odometer displays the message WARN ENG.
An Out of Range HIGH code 125 will be set by the ECM if the signal voltage is greater than 4.9V for more than 1.0 seconds.
Diagnostic Trouble Code 125 may be set by an open return circuit (ground), short to a voltage source on the ICP signal circuit or a defective sensor.
Diagnostic Trouble Code 332
ATA Code, PID 164, FMI 13
Injection Control Pressure above Specification with Engine Off
When code 332 is active the amber ENGINE lamp is illuminated and the odometer displays the message WARN ENG.
Diagnostic Trouble Code 332 will be set by the ECM if the signal from the ICP sensor is higher than expected with the engine not running. If the ECM detects this fault, the ECM will ignore the ICP signal and will operate the IPR with fixed values determined from engine operating conditions.
Code 332 may be caused by a defective sensor or a biased circuit.