SPN 105 - FMI 4 (Fault Code 154)
Friday, July 20, 2018
Fault Codes CUMMINS GTA38 K38 K50 QSK38 QSK50/60 CM850,
Fault Codes CUMMINS Signature ISX QSX15 CM570
SPN105 FMI4
Intake Manifold 1 Temperature Sensor Circuit - Voltage Below Normal or Shorted to Low Source
CODES:
Fault Code: 154
PID(P), SID(S): P105
SPN: 105
FMI: 4/4
Lamp: Amber
REASON: Low signal voltage detected at intake manifold air temperature circuit.
EFFECT: Fan will stay ON if controlled by the engine control module (ECM).
Circuit Description:
The Engine Control Module (ECM) provides 5 volts to the intake manifold temperature signal circuit, and monitors the change in voltage caused by changes in the resistance of the sensor to determine the intake manifold temperature. When the intake air is cold, the sensor (or thermistor) resistance is high. The ECM signal voltage only pulls down a small amount through the sensor to a ground. Therefore, the ECM senses a high signal voltage or low temperature. When the intake air is warm, the sensor resistance is low. The signal voltage pulls down a large amount. Therefore, the ECM senses a low signal voltage, or a high temperature.
Component Location:
The intake manifold 1 pressure/temperature sensor is located in the air intake manifold.
Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.
Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the intake manifold temperature signal voltage was out of range low.
Action Taken When the Fault Code is Active:
• The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
• A default value is used for the intake manifold temperature reading.
Conditions for Clearing the Fault Code:
• To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
• The fault code status displayed by the recommended Cummins® electronic service tool or equivalent will change to INACTIVE immediately after the diagnostic runs and passes.
• The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
• The "Reset All Faults" command in the recommended Cummins® electronic service tool or equivalent can be used to clear active and inactive faults.
Shop Talk:
The intake manifold temperature sensor shares return wires in the engine harness with other sensors. Opens and shorts in the engine harness can cause multiple fault codes to be active. Check fault codes with multiple counts first.
Possible causes of this fault code include:
• Signal circuit shorted to ground in the harness.
• Signal circuit shorted to return or ground in the sensor.
A malfunctioning intake manifold temperature sensor.
Read More:
SPN 105 - FMI 0 (Fault Code 155)
SPN 3510 - FMI 4 (Fault Code 187)
Blog.Teknisi
Intake Manifold 1 Temperature Sensor Circuit - Voltage Below Normal or Shorted to Low Source
 |
| Intake Manifold Pressure/Temperature Sensor Circuit |
CODES:
Fault Code: 154
PID(P), SID(S): P105
SPN: 105
FMI: 4/4
Lamp: Amber
REASON: Low signal voltage detected at intake manifold air temperature circuit.
EFFECT: Fan will stay ON if controlled by the engine control module (ECM).
Circuit Description:
The Engine Control Module (ECM) provides 5 volts to the intake manifold temperature signal circuit, and monitors the change in voltage caused by changes in the resistance of the sensor to determine the intake manifold temperature. When the intake air is cold, the sensor (or thermistor) resistance is high. The ECM signal voltage only pulls down a small amount through the sensor to a ground. Therefore, the ECM senses a high signal voltage or low temperature. When the intake air is warm, the sensor resistance is low. The signal voltage pulls down a large amount. Therefore, the ECM senses a low signal voltage, or a high temperature.
Component Location:
The intake manifold 1 pressure/temperature sensor is located in the air intake manifold.
Conditions for Running the Diagnostics:
This diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.
Conditions for Setting the Fault Codes:
The Engine Control Module (ECM) detected the intake manifold temperature signal voltage was out of range low.
Action Taken When the Fault Code is Active:
• The ECM illuminates the amber CHECK ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.
• A default value is used for the intake manifold temperature reading.
Conditions for Clearing the Fault Code:
• To validate the repair, perform a key cycle, start the engine and let it idle for 1 minute.
• The fault code status displayed by the recommended Cummins® electronic service tool or equivalent will change to INACTIVE immediately after the diagnostic runs and passes.
• The ECM will turn off the amber CHECK ENGINE lamp immediately after the diagnostic runs and passes.
• The "Reset All Faults" command in the recommended Cummins® electronic service tool or equivalent can be used to clear active and inactive faults.
Shop Talk:
The intake manifold temperature sensor shares return wires in the engine harness with other sensors. Opens and shorts in the engine harness can cause multiple fault codes to be active. Check fault codes with multiple counts first.
Possible causes of this fault code include:
• Signal circuit shorted to ground in the harness.
• Signal circuit shorted to return or ground in the sensor.
A malfunctioning intake manifold temperature sensor.
Read More:
SPN 105 - FMI 0 (Fault Code 155)
SPN 3510 - FMI 4 (Fault Code 187)
Blog.Teknisi
0 Response to "SPN 105 - FMI 4 (Fault Code 154)"
Post a Comment