Cummins ISB6.7 CM2150 (2007-09) Fault Code: 256 PID: 171 SPN: 171 FMI: 4 Ambient Air Temperature Sensor 1 Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the ambient air temperature circuit.
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, recalibrate the ECM.
The ambient air 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:
1)Signal circuit shorted to ground in the harness
2)Signal circuit shorted to return or ground in the sensor.
Possible repairs:
1)Replace the ambient air temperature sensor.
2)Repair or replace the engine harness.
3)Replace the ECM.
-
Wabco ToolBox plus 13.7 + ECAS CAN2 v3.00 Diagnostics Software
Trucks software $84.00Rated 0 out of 5
-
DOWNLOAD Paccar ESA Electronic Service Analyst 5.5.0 Diagnostic Software 2023
PACCAR $96.00Rated 0 out of 5
Related products
-
Allison 1000 & 2000 Gen 4 Fault Codes: U1301 J1850 (Class 2) Serial Data Communication Link Low
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: P0218 Transmission Fluid Over Temperature Condition
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: U0073 CAN Bus Reset Counter Overrun
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: P2810 Solenoid G Electrical
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: P0122 Pedal Position Sensor Circuit Low Voltage
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: P1688 Unmanaged Engine Torque Delivered To TCM Signal
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: U0100 CAN Bus ECM Error
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: U1064 J1850 (Class 2) TBC Controller State of Health Failure
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: P0876 Transmission Reverse Pressure Switch Circuit Stuck Open
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: P0875 Transmission Reverse Pressure Switch Circuit Malfunction
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: P0848 Transmission Pressure Switch Solenoid D Circuit High
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: P0871 Transmission Pressure Switch Solenoid E Circuit Stuck Open
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: U1096 J1850 (Class 2) IPC Controller State of Health Failure
1000 & 2000 Gen 4 $50.00Rated 0 out of 5 -
Allison 1000 & 2000 Gen 4 Fault Codes: U1041 J1850 (Class 2) ABS Controller State of Health Failure
1000 & 2000 Gen 4 $50.00Rated 0 out of 5
-
SERVICE MANUAL Eaton Fuller – Autoshift, Autoselect Service Manual (TRSM-0050)
EATON $25.00Rated 0 out of 5