System Operation Description:
Use this procedure to determine if the neutral switch is preventing normal operation of cruise control, idle set speed, or PTO operation:
The following switch circuits can also prevent the correct operation of the cruise control, idle set speed or PTO operation:
• Service Brake Pedal Position (Switch 1)
• Service Brake Pedal Position (Switch 2)
• Cruise Control Set/Resume Switch
• Cruise Control On/Off Switch
• PTO On/Off Switch
The switches are described in the respective circuit tests in Troubleshooting.
All of the following customer programmable parameters can affect cruise control, idle set speed,
and PTO operation:
• “Low Cruise Control Speed Set Limit”
• “High Cruise Control Speed Set Limit”
• “Idle Vehicle Speed Limit”
• “Cruise/Idle/PTO Switch Configuration”
• “Idle/PTO Bump rpm”
• “Idle/PTO rpm Ramp Rate”
• “PTO Vehicle Speed Limit”
The vehicle speed calibration can also affect the cruise control, the idle set speed, and the PTO if the vehicle speed calibration is incorrectly programmed. Refer to Troubleshooting, “Customer Specified Parameters”.
Transmission Neutral Switch
The transmission neutral switch is required when the “Transmission Style” parameter is programmed to “Automatic Option 3” or “Automatic Option 4”. This switch is used to indicate when the automatic transmission is in neutral.
The transmission neutral switch is an open circuit when the transmission is in gear. Shifting the transmission to the neutral position should close the circuit, which connects the input to the battery voltage. Many other switches in the system connect the input to ground when the circuit is closed.
Usage of Transmission Style Switches
The “Transmission Style” parameter determines the switches that will be used. The following switches can be used with being dependent on the parameter setting:
• Clutch Pedal Position
• Neutral
• Service Brake Pedal Position (Switch 1)
• Service Brake Pedal Position (Switch 2)
Refer to Table 149 for additional information.
Test Step 1. Determine the Type of Problem
A. Connect the electronic service tool to the data link connector.
B. Turn the key switch to the ON position.
C. If the vehicle will not allow setting a cruise speed, an idle speed or a PTO speed, check the following customer parameters:
Cruise Control Parameters
• “Low Cruise Control Speed Set Limit”
• “High Cruise Control Speed Set Limit”
Idle Parameters
• “Idle Vehicle Speed Limit”
• “Idle RPM Limit”
• “Top Engine Limit” (TEL)
PTO Parameters
• “PTO Configuration”
• “PTO Vehicle Speed Limit”
D. Ensure that the vehicle is not experiencing a problem due to one of these parameters. Refer to Troubleshooting, “Customer Specified Parameters” for a description of the parameters, if necessary.
E. Check the status screen on the electronic service tool that indicates the last cause of a kickout for one of the following modes:
• Cruise Kickout
• Idle Kickout
• PTO Kickout
Expected Result:
The problem is due to a parameter setting or the problem is due to a normal kickout.
Results:
• OK – Explain the proper operation of system to the driver. STOP.
• Not OK
Repair: If a problem is still suspected with the neutral switch circuit perform the following procedure:
Proceed to Test Step 2.
Test Step 2. Inspect Electrical Connectors and Wiring
A. Thoroughly inspect the J1/P1 ECM connector, the firewall bulkhead connector and the terminals for the following switches in the connectors:
• J1/P1:62 (Neutral Switch) Refer to Troubleshooting, “Electrical Connectors – Inspect” for details.
B. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the switches.
Refer to Illustration 127.
C. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).
D. Check the harness and wiring for abrasion and pinch points from the sensor to the ECM.
Expected Result:
All connectors, pins, and sockets should be completely coupled and/or inserted and the harness and wiring should be free of corrosion, abrasion, or pinch points.
Results:
• OK – Proceed to Test Step 3.
• Not OK
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.
STOP.
Test Step 3. Check the Status of the “Transmission Neutral Switch”
A. Access the status screen on the electronic service tool.
B. Turn the key switch to the ON position.
C. Shift the transmission into the Neutral position while the status for the “Transmission Neutral Switch” is being observed. Also, shift out of neutral while the status for the “Transmission Neutral Switch” is being observed.
Note: If the status indicates “Not Installed”, check the programming of the “Transmission Style” parameter. The “Transmission Style” must be programmed to “Automatic Option 3” or “Automatic Option 4”.
Expected Result:
The switch status changes per the information in Table 150.
Results:
• OK – The switch is operating normally. STOP.
• Intermittent Problem Suspected – Proceed to Test Step 4.
• Not OK – The ECM is not reading the switch status change. Proceed to Test Step 5.
Test Step 4. Operate the Vehicle and Check the Kickout Status Parameter
A. For an intermittent cruise control kickout, talk to the driver in order to determine the conditions when the kickout occurs. Topics of examination could be the following examples:
• Specific Speed
• Road Conditions
• Weather Conditions
Take the vehicle for a road test in order to duplicate these conditions and set the cruise control. Operate the vehicle in cruise control until the problem reoccurs.
B. For an intermittent idle kickout, talk to the driver in order to determine the conditions when the kickout occurs. A topic of examination could be the following example:
• Specific engine rpm
Start the engine. Duplicate these conditions and set the idle rpm. Operate the vehicle in idle until the problem reoccurs.
Note: The status screen on the electronic service tool will only indicate the last kickout. The status screen on the electronic service tool will lose this information if the key switch is turned OFF.
C. Connect the electronic service tool and check the status screen for the last cause of the kickout.
D. If the status screen on the electronic service tool is blank, then either there was no kickout of the cruise control, or the power to the ECM was turned off before the information could be read. Repeat this test step.
Note: A status screen that is blank indicates No Occurrence.
Expected Result:
RESULT 1 The status for the kickout displays the following result:
• “Neutral”
RESULT 2 The status for the kickout displays the following result:
• “Switch Turned Off”
RESULT 3 The status for the kickout displays the following result:
• “Brake”
RESULT 4 The status for the kickout displays the following result:
• “Vehicle Speed < Limit”
• “Bad Vehicle Speed”
• “Vehicle Speed ? Limit”
RESULT 5 The status for the kickout displays the following result:
• “PTO Switch ON”
RESULT 6 The status for the kickout displays the following result:
• “Clutch”
RESULT 7 The status for the kickout displays the following result:
• “No Engine Speed”
Results:
• Result 1 – Proceed to Test Step 5.
• Result 2
Repair: Perform the following diagnostic
procedure:
Troubleshooting, “Cruise Control Switch Circuit – Test”
STOP.
• Result 3
Repair: Perform the following diagnostic
procedure:
Troubleshooting, “Service Brake Pedal Position
(Switch 1) Circuit – Test”
STOP.
• Result 4
Repair: Perform the following diagnostic
procedure:
Troubleshooting, “Vehicle Speed Circuit – Test”
STOP.
• Result 5
Repair: Perform the following diagnostic
procedure:
Troubleshooting, “PTO Switch Circuit – Test”
STOP.
• Result 6
Repair: Perform the following diagnostic
procedure:
Troubleshooting, “Clutch Pedal Position Switch Circuit – Test” STOP.
• Result 7
Repair: Perform the following diagnostic
procedure:
Troubleshooting, “Engine Speed/Timing Circuit – Test”
STOP.
Test Step 5. Check the Switch Circuit for the ECM
A. Turn the key switch to the OFF position.
B. Fabricate a jumper wire 100 mm (4 inch) long.
Crimp a Deutsch pin to both ends of the wires.
C. Disconnect the P1 ECM connector from the ECM.
D. Connect a 140-2266 Cable (Seventy-Pin Breakout) between the P1 ECM connector and the ECM.
E. Install the jumper into terminal 62 (Neutral Switch) of the breakout T. Connect the other end of the jumper to terminal 52 (Unswitched +Battery) of the breakout T.
F. Turn the key switch to the ON position.
G. Connect the electronic service tool to the data link connector.
H. Access the status screen on the electronic service tool.
I. While the status for the “Transmission Neutral Switch” is being monitored on the status screen slowly remove the jumper from terminal 52 (Unswitched +Battery). Now, slowly insert the jumper into terminal 52 (Unswitched +Battery).
Expected Result:
When the jumper wire is installed, the status for the “Transmission Neutral Switch” is “On”. When the jumper wire is removed, the status for the “Transmission Neutral Switch” is “Off”.
Results:
• OK – The ECM is functioning properly. Proceed to Test Step 6.
• Not OK – The ECM is not functioning properly.
Repair: Perform the following repair:
1. Temporarily connect a test ECM.
2. Remove all jumpers and replace all connectors.
3. Recheck the system for active diagnostic codes.
4. Repeat the Test Step.
5. If the problem is resolved with the test ECM, reconnect the suspect ECM.
6. If the problem returns with the suspect ECM, replace the ECM.
7. Verify that the repair eliminates the problem.
STOP.
Test Step 6. Insert a Jumper at the Neutral Switch
A. Turn the key switch to the OFF position.
B. Ensure that the J1/P1 ECM connector is connected.
C. Find the neutral switch in the vehicle.
D. Disconnect the wires from the neutral switch terminals.
E. Turn the key switch to the ON position.
F. Connect the electronic service tool to the data link connector.
G. Access the status screen on the electronic service tool.
H. While the status for the “Transmission Neutral Switch” is being monitored, connect the switch wires and disconnect the switch wires.
Expected Result:
When the switch wires are connected, the status for the “Transmission Neutral Switch” is “On”. When the switch wires are disconnected, the status for the “Transmission Neutral Switch” is “Off”.
Results:
• OK – The switch is not functioning properly.
Repair: Perform the following repair:
Replace the faulty switch.
Verify that the repair eliminates the problem.
STOP.
• Not OK – There is a problem in the harness between the switch and the ECM. Proceed to Test
Step 7.
Test Step 7. Insert a Jumper at the Bulkhead Connector
A. Turn the key switch to the OFF position.
B. Fabricate a jumper wire 100 mm (4 inch) long.
Crimp a Deutsch pin to each end of the wires.
C. Find the neutral switch terminal and the +Battery connection in the engine side of the bulkhead connector for the vehicle harness.
D. Insert the jumper wire between the two terminals in the engine side of the bulkhead connector.
E. Turn the key switch to the ON position.
F. Connect the electronic service tool to the data link connector.
G. Access the status screen on the electronic service tool.
H. While the switch status is being monitored, alternately remove the jumper wire between the two terminals, and alternately insert the jumper wire between the two terminals.
Expected Result:
When the jumper wire is installed, the status for the “Transmission Neutral Switch” is “On”. When the jumper wire is removed, the status for the “Transmission Neutral Switch” is “Off”.
Results:
• OK – The problem is in the vehicle wiring
between the bulkhead connector and the switch.
Repair: Perform the following repair: Inspect the vehicle wiring and repair the vehicle wiring, as required. If the problem still exists with the wiring, send the vehicle to the OEM dealer.
STOP.
• Not OK – The problem is in the vehicle wiring between the bulkhead connector and the ECM.
Repair: Perform the following repair:
Inspect the vehicle wiring and repair the vehicle wiring, as required. If the problem still exists with the wiring, send the vehicle to the OEM dealer.
STOP.
