Circuit Description The oil pressure sensor is used by the electronic control module (ECM) to monitor the lubricating oil pressure. The ECM monitors the voltage on the signal pin and converts this to a pressure value. The oil pressure value is used by the ECM for the engine protection system.
Component Location The oil pressure sensor is located on the engine block, below and to the right of the ECM.
Shop Talk 1) If Fault Code 143 or 415 is not present, the problem is not related to the engine lubrication system. 2) Your diagnostic tool can be used to monitor the oil pressure signal voltage going into the ECM.
Circuit Description The remote throttle pedal provides the driver’s throttle command to the electronic control module (ECM) through the original equipment manufacturer’s (OEM) harness and the OEM interface harness. The ECM uses this signal to determine the fueling command.
Component Location The remote throttle pedal location varies with each OEM. Refer to the OEM manual.
Shop Talk The remote throttle position sensor is a potentiometer. The resistance specifications of the throttle position sensor is as follows: 1) Between supply and return = 2000 to 3000 ohms 2) Between supply and signal: Released = 1500 to 3000 ohms; depressed = 200 to 1500
NOTE: If the remote throttle position sensor is changed, or after a calibration download, cycle the throttle pedal (keyswitch in the ON position) through its complete travel three times. This procedure calibrates the new remote throttle with the ECM. 1) The remote throttle enable switch must be turned on for the remote throttle to operate. 2) Possible causes of this fault code include an open circuit in the supply wire, short circuit to ground in the supply or signal wires, defective remote throttle position sensor, or a failed ECM power supply.
Circuit Description The remote throttle pedal provides the driver’s throttle command to the electronic control module (ECM) through the OEM harness and the original equipment manufacturer’s (OEM) interface harness. The ECM uses this signal to determine the fueling command.
Component Location The remote throttle pedal location varies with each OEM. Refer to the OEM manual.
Shop Talk The throttle position sensor is a potentiometer. The resistance specifications of the throttle position sensor is as follows: 1) Between supply and return = 2000 to 3000 ohms 2) Between supply and signal: Released = 1500 to 3000 ohms; depressed = 200 to 1500
Note: If the throttle or throttle position sensor is changed, or after a calibration download, cycle the throttle pedal (keyswitch in the ON position) through its complete travel three times. This procedure calibrates the new throttle with the ECM. 1) The remote throttle enable switch must be turned on for the remote throttle to operate. 2) Possible causes of this fault code include an open circuit in the return wire, short circuit to +5 VDC or 12 VDC, defective remote throttle position sensor or a failed ECM power supply.
Circuit Description The accelerator position sensor is attached to the accelerator pedal. The accelerator position sensor sends a signal to the electronic control module (ECM) when the driver pushes on the accelerator pedal. The accelerator position circuit contains three wires: a +5-VDC SUPPLY wire (pin 29), a RETURN ground (pin 19), and a SIGNAL wire (pin 30).
NOTE: The connector pin letters shown for the accelerator pedal wiring in these troubleshooting steps are examples of representative sensors. The connector pin assignments can vary with equipment manufacturer, but the base troubleshooting logic will still apply.
Component Location The accelerator position sensor is located on the accelerator pedal.
Shop Talk If all wiring and sensor checks look in good order, replace the accelerator position sensor and the idle validation switch circuit wires between the accelerator pedal and the ECM with new wires. Run the wires through, or around, the bulkhead without using the bulkhead connector. Test the truck with the test wires in place. If the fault goes away, replace the OEM harness. Seal the openings in the bulkhead around the connector and wires to prevent engine compartment fumes from entering the cab area.
NOTE: The three wires in the accelerator position sensor circuit must be twisted together. The same applies for the three wires in the idle validation switch circuit.
NOTE: If pin 19 (RETURN) and pin 30 (SIGNAL) are reversed, throttle position will only read 50 percent.
Circuit Description The accelerator position sensor is attached to the accelerator pedal. The accelerator position sensor sends a signal to the electronic control module (ECM) when the driver pushes on the accelerator pedal. The accelerator position circuit contains three wires: a +5-VDC SUPPLY wire (pin 29), a RETURN ground (pin 19), and a SIGNAL wire (pin 30).
NOTE: The connector pin letters shown for the accelerator pedal wiring in these troubleshooting steps are examples of representative sensors. The connector pin assignments can vary with equipment manufacturer, but the base troubleshooting logic will still apply.
Component Location The accelerator position sensor is located on the accelerator pedal.
Shop Talk If all wiring and sensor checks look in good order, replace the accelerator position sensor and the idle validation switch circuit wires between the accelerator pedal and the ECM with new wires. Run the wires through, or around, the bulkhead without using the bulkhead connector. Test the truck with the test wires in place. If the fault goes away, replace the OEM harness. Seal the openings in the bulkhead around the connector and wires to prevent engine compartment fumes from entering the cab area.
NOTE: The three wires in the accelerator position sensor circuit must be twisted together. The same applies for the three wires in the idle validation switch circuit.
NOTE: If pin 19 (RETURN) and pin 30 (SIGNAL) are reversed, throttle position will only read 50 percent.
Circuit Description The accelerator position sensor is attached to the accelerator pedal. The accelerator position sensor sends a signal to the electronic control module (ECM) when the driver pushes on the accelerator pedal. The accelerator position circuit contains three wires: a +5-VDC supply wire (pin 29), a return ground (pin 19), and a signal wire (pin 30).
NOTE: The connector pin letters shown for the accelerator pedal wiring in these troubleshooting steps are examples of representative sensors. The connector pin assignments can vary with equipment manufacturer, but the base troubleshooting logic will still apply.
Component Location The accelerator position sensor is located on the accelerator pedal.
Shop Talk If all wiring and sensor checks look in good order then replace the accelerator position sensor and the idle validation switch circuit wires between the accelerator pedal and the ECM with new wires. Run the wires through, or around, the bulkhead without using the bulkhead connector. Test the truck with the test wires in place. If the fault goes away, replace the OEM harness. Seal the openings in the bulkhead around the connector and wires to prevent toxic and noxious fumes from entering the operator area.
NOTE: The three wires in the accelerator position sensor circuit must be twisted together. The same applies for the three wires in the idle validation switch circuit.
NOTE: If pin 19 (return) and pin 30 (signal) are reversed, throttle position will only read 50 percent.
Circuit Description The accelerator position sensor is attached to the accelerator pedal. The accelerator position sensor sends a signal to the electronic control module (ECM) when the driver pushes on the accelerator pedal. The accelerator position circuit contains three wires: a +5-VDC supply wire (pin 29), a return ground (pin 19), and a signal wire (pin 30).
NOTE: The connector pin letters shown for the accelerator pedal wiring in these troubleshooting steps are examples of representative sensors. The connector pin assignments can vary with equipment manufacturer, but the base troubleshooting logic will still apply.
Component Location The accelerator position sensor is located on the accelerator pedal.
Shop Talk If all wiring and sensor checks look in good order then replace the accelerator position sensor and the idle validation switch circuit wires between the accelerator pedal and the ECM with new wires. Run the wires through, or around, the bulkhead without using the bulkhead connector. Test the truck with the test wires in place. If the fault goes away, replace the OEM harness. Seal the openings in the bulkhead around the connector and wires to prevent toxic and noxious fumes from entering the operator area.
NOTE: The three wires in the accelerator position sensor circuit must be twisted together. The same applies for the three wires in the idle validation switch circuit.
NOTE: If pin 19 (return) and pin 30 (signal) are reversed, throttle position will only read 50 percent.
Circuit Description The intake manifold pressure sensor monitors intake manifold pressure and passes information to the electronic control module (ECM) through the sensor harness. If the intake manifold pressure becomes too high, it will cause a derate condition.
Component Location The intake manifold pressure sensor is located on the rear of the intake air manifold in the second port on the side of the head to the right of the fuel filter.
Shop Talk 1) Determine if engine is being overfueled. 2) Confirm that the correct intake manifold pressure sensor part number is being used. 3) Confirm that the correct turbocharger is being used. 4) If it is suspected that cold intake air is the cause of the high intake manifold pressure, test the engine with warm intake air. 5) Check for high restriction in the intake air manifold due to a shutdown device in the manifold (if the vehicle is equipped with one). Do not remove this device. If the engine is operated in a flammable atmosphere, the device is an essential safety feature.
Circuit Description The intake manifold pressure sensor monitors intake manifold pressure and passes information to the electronic control module (ECM) through the sensor harness. If the intake manifold pressure becomes too high, it will cause a derate condition.
Component Location The intake manifold pressure sensor is located on the rear of the intake air manifold in the second port on the side of the head to the right of the fuel filter.
Shop Talk 1) Determine if engine is being overfueled. 2) Confirm that the correct intake manifold pressure sensor part number is being used. 3) Confirm that the correct turbocharger is being used. 4) If it is suspected that cold intake air is the cause of the high intake manifold pressure, test the engine with warm intake air. 5) Check for high restriction in the intake air manifold due to a shutdown device in the manifold (if the vehicle is equipped with one). Do not remove this device. If the engine is operated in a flammable atmosphere, the device is an essential safety feature.
Circuit Description The engine speed sensor provides engine speed information to the engine control module (ECM). The sensor must be powered up by (+) 5 VDC to operate. The sensor generates its signals by sensing the movement of target teeth machined into a tone wheel that is mounted to the crankshaft. The tone wheel has 35 teeth and a gap where the 36th tooth would be placed. This missing tooth indicates cylinder 1 and 6 are at top dead center.
Component Location The engine speed sensor is located on the intake side of the engine block, at crankshaft level, between cylinders 4 and 5 on ISB and QSB5.9 engine with the Bosch fuel system.
Shop Talk This fault code will also cause a fuel derate. This could be the cause of a low-power complaint. Also, this fault code can cause starting problems in cold weather. ISB and QSB engines with the fuel pump system use separate sensors for engine speed and position.
