SPN 157 - FMI 4 (Fault Code 452)
SPN 157 - FMI 4 (Fault Code: 452)
SPN157 FMI4
CODES:
Fault Code: 451
PID(P), SID(S): P157
SPN: 157
FMI: 3
Lamp: AMBER
SRT:
REASON: Injector Metering Rail Number 1 Pressure Sensor Circuit - Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the rail fuel pressure sensor circuit.
EFFECT: Power and or speed derate.
Circuit Description:
The fuel delivery pressure sensor responds to pressure changes in the fuel rail. The fuel delivery pressure sensor has a 5 volt supply circuit, a sensor signal voltage, and a return circuit. The electronic control module (ECM) provides a 5 volt supply to the fuel rail pressure sensor using a common sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The fuel rail pressure sensor provides a signal to the ECM on the fuel rail pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure in the fuel rail. The ECM will detect a low signal voltage at high rail pressures. The ECM will detect a high signal voltage
during low rail pressure conditions.
Component Location:
The fuel pressure sensor is installed in the fuel rail.
Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position.
Conditions for Setting the Fault Codes:
The ECM detects that the fuel delivery pressure signal voltage is greater than 4.80-VDC for more than 1 second.
Action Taken When the Fault Code is Active:
• The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
• A default value for the fuel rail pressure reading is used.
Conditions for Clearing the Fault Code:
The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.
Shop Talk:
Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM.
This fault code will become inactive anytime the keyswitch is ON and the signal pin of the ECM is too low. This can be caused by a short circuit to ground on the +5 volt supply or signal wire. This fault will also become active if a device that is powered by the common +5-VDC power supply is shorted to ground. This fault code will become inactive any time the keyswitch is ON and the signal returns to a valid in-range voltage.
Causes for this fault code include:
• Engine harness; the supply or signal wire is shorted to ground
• Other components; any component connected to the common power supply is shorted to ground
• Damaged sensor
• Damaged ECM.
Read More:
SPN 157 - FMI 3 (Fault Code 451)
SPN 157 - FMI 0 (Fault Code 449) CL
Blog.Teknisi
 |
| ISC and ISL with CM2150 - Fuel Rail Pressure Sensor Circuit |
CODES:
Fault Code: 451
PID(P), SID(S): P157
SPN: 157
FMI: 3
Lamp: AMBER
SRT:
 |
| ISB with CM2150 - Fuel Rail Pressure Sensor Circuit |
REASON: Injector Metering Rail Number 1 Pressure Sensor Circuit - Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the rail fuel pressure sensor circuit.
EFFECT: Power and or speed derate.
Circuit Description:
The fuel delivery pressure sensor responds to pressure changes in the fuel rail. The fuel delivery pressure sensor has a 5 volt supply circuit, a sensor signal voltage, and a return circuit. The electronic control module (ECM) provides a 5 volt supply to the fuel rail pressure sensor using a common sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The fuel rail pressure sensor provides a signal to the ECM on the fuel rail pressure sensor signal circuit. This sensor signal voltage changes, based on the pressure in the fuel rail. The ECM will detect a low signal voltage at high rail pressures. The ECM will detect a high signal voltage
during low rail pressure conditions.
Component Location:
The fuel pressure sensor is installed in the fuel rail.
Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position.
Conditions for Setting the Fault Codes:
The ECM detects that the fuel delivery pressure signal voltage is greater than 4.80-VDC for more than 1 second.
Action Taken When the Fault Code is Active:
• The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
• A default value for the fuel rail pressure reading is used.
Conditions for Clearing the Fault Code:
The ECM will turn off the amber CHECK ENGINE light immediately after the diagnostic runs and passes.
Shop Talk:
Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe™ Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM.
This fault code will become inactive anytime the keyswitch is ON and the signal pin of the ECM is too low. This can be caused by a short circuit to ground on the +5 volt supply or signal wire. This fault will also become active if a device that is powered by the common +5-VDC power supply is shorted to ground. This fault code will become inactive any time the keyswitch is ON and the signal returns to a valid in-range voltage.
Causes for this fault code include:
• Engine harness; the supply or signal wire is shorted to ground
• Other components; any component connected to the common power supply is shorted to ground
• Damaged sensor
• Damaged ECM.
Read More:
SPN 157 - FMI 3 (Fault Code 451)
SPN 157 - FMI 0 (Fault Code 449) CL
Blog.Teknisi
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