0172839 JOHNSON TILT LINE ASSY., Upper

Illustration 1 g00642016
This is a typical schematic for cab accelerator pedal position sensor.
The return wire may be connected to P1-3, P1-5, or P1-18.
Illustration 2 g01150754
Pin locations for ECM connector
(P1-3) Input sensor
(P1-4) + 8V
(P1-5) "Accelerator pedal sensor/switch sensor" Test Step 1. Inspect Electrical Connectors and Wiring
Thoroughly inspect ECM vehicle harness connector J1/P1, the firewall bulkhead connector and the accelerator pedal position sensor connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the accelerator pedal position sensor:
P1-3
P1-4
P1-5
P1-66
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasion and pinch points from the accelerator pedal position sensor to the ECM. Expected Result:All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Perform the following repair:Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect Cat ET to the data link connector.
Turn the ignition key switch to the ON position.
Monitor the active diagnostic code screen on Cat ET. Check and record active diagnostic codes. Note: When the ECM automatically calibrates new duty cycle values for the low idle throttle position and the high idle throttle position the ECM assumes 22 percent duty cycle at low idle and 75 percent duty cycle at high idle. As a result, you may notice that the throttle position status reaches 100 percent well before the accelerator pedal is fully depressed. This is normal. After some cycling of the accelerator pedal to the high idle position, the ECM will adjust the calibration automatically. The ECM will adjust the calibration automatically provided that the high idle stop position is within the 75 to 90 percent duty cycle range, and the low idle is in the 10 to 22 percent duty cycle range. During normal operation, you may also notice that more movement of the accelerator pedal is required for the throttle position status to increase above three percent. You may also observe that the status reaches the 100 percent value prior to the limit of the high idle position. This is done in order to ensure that the throttle reaches these two critical points for engine operation.Expected Result:Result 1 Diagnostic Code 91-08 or 91-13 is active.Result 2 Diagnostic Code 41-03 or 41-04 is active.Result 3 There are no active diagnostic codes that are related to the accelerator pedal position sensor circuit at this time, but a problem is suspected with operation of the accelerator pedal position sensor circuit.Results:
Result 1 - Proceed to Test Step 3.
Result 2 - Proceed to Test Step 5.
Result 3 - Proceed to Test Step 3.Test Step 3. Check the Duty Cycle of the Accelerator Pedal Position Sensor
Verify that the ignition key switch is in the ON position.
Monitor the duty cycle of the throttle sensor on Cat ET. Access the following display screens in order:
"Service"
"Calibrations"
"Monitor Throttle Position Sensor"Expected Result:The duty cycle is between 10 and 22 percent with the accelerator pedal assembly in the Low Idle position, and the duty cycle is between 75 and 90 percent with the accelerator pedal assembly in the High Idle position.Results:
OK - The accelerator pedal position sensor is operating correctly. Proceed to Test Step 6.
Not OK - The accelerator pedal position sensor circuit is not operating correctly. Proceed to Test Step 4.Test Step 4. Check the Supply Voltage at the Sensor for the Accelerator Pedal Position Sensor
Turn the ignition key switch to the OFF/RESET position.
Install a breakout T with three terminals at the accelerator pedal position sensor connector J403/P403.
Turn the ignition key switch to the ON position.
Measure the voltage at terminal "A" (+8 V) with reference to terminal "B" (accelerator/switch sensor common). Expected Result:The measured voltage is between 7.5 VDC and 8.5 VDC for the pedal mounted throttle position sensor that is used in the cab.Results:
OK - Proceed to Test Step 8.
Not OK - The sensor is not receiving the correct voltage. Proceed to Test Step 5.Test Step 5. Monitor Cat ET while the Accelerator Pedal Position Sensor is Being Disconnected
Access the active diagnostic code screen on Cat ET. Ensure that one of the following diagnostic code is active before proceeding:
41-03 (21)
41-04 (21)
Monitor the active diagnostic code screen while the accelerator pedal position sensor is being disconnected and reconnected. Expected Result:One of the following diagnostic codes is still active after the accelerator pedal position sensor has been disconnected:
41-03 (21)
41-04 (21)Results:
OK - Ensure that the accelerator pedal position sensor has been reconnected before continuing. Proceed to Test Step 7.
Not OK - Repair: Perform the following diagnostic procedure:Temporarily install another accelerator pedal position sensor. Use Cat ET to check for an active +8 V diagnostic code. Replace the accelerator pedal position sensor if both of the following conditions occur:
The problem is corrected with the new accelerator pedal position sensor.
The problem returns after the old accelerator pedal position sensor has been reconnected.STOPTest Step 6. Check the Status of the PTO On/Off Switch and the Status of the Power Train Data Link with Cat ET
Check the status of the "PTO ON/OFF Switch" on Cat ET in order to verify that the "PTO ON/OFF Switch" is off. The PTO mode may cause the ECM to ignore the accelerator pedal posit