Use this procedure under the following situation:
A problem is suspected with the operation of the warning lamp.
The following background information is related to the following procedure:
Warning Lamp Operation
A warning lamp is required if the "Engine Monitoring" feature is used. The warning lamp indicates an active problem with one of the monitored conditions such as high coolant temperature. A flashing warning lamp indicates that the engine is derating power. The warning lamp will turn on for a minimum of two seconds after the engine has started.
With OCT99 and newer software, a new parameter is available to provide the option of using a single warning lamp or multiple warning lamps. The programmable "Engine Montoring Lamps" parameter provides the option of using a single warning lamp for all monitored conditions, or discrete lamps for each monitored condition. If the "Engine Monitoring Lamps" parameter is programmed to "Warning Lamp", then J1/P1:29 is used for the connection of a single warning lamp. If the "Engine Monitoring Lamps" parameter is programmed to "Option 1", then J1/P1:29 is used to connect a lamp for Low Oil Pressure Warning and J1/P1:31 is used to connect a lamp for High Coolant Temperature Warning. If an optional Coolant Level Sensor is also installed then J1/P1:30 is used to connect a Low Coolant Level Warning Lamp. The "Coolant Level Sensor" parameter must be programmed to "4-pin".
If a Coolant Level Sensor is not installed or the "Engine Monitoring Lamps" parameter is programmed to "Warning Lamp", then J1/P1:30 will function as a PTO Switch On Lamp output. The parameter for the "Coolant Level Sensor" must be programmed to "NO" if the sensor is not installed.
Operation of Engine Monitoring
When the ECM has detected an engine condition that exceeds the acceptable limits, the warning lamp will turn on. The activation of the lamp depends on the existing conditions and the programming of the parameter for "Engine Monitoring". The lamp will activate in one of the following modes:
- The lamp not only turns on, but the lamp stays on.
- The lamp will flash on and off.
If the lamp turns on continuously, the engine is in warning mode. If the lamp begins to flash, the ECM has begun to derate engine speed, vehicle speed, or power.
If the parameter for engine monitoring is programmed to "Warning", the lamp will not flash. The lamp only flashes when the engine is programmed to "Derate" or "Shutdown".
If the Customer Parameter for Engine Monitoring is programmed to "Warning", "Derate", or "Shutdown" the lamp will turn on when a warning condition exists. The lamp will be turned on continuously while a warning condition exists.
If the customer parameter for engine monitoring is programmed to "Derate" or "Shutdown", the lamp flashes whenever engine monitoring is derating engine speed, vehicle speed, and power.
If the customer parameter for engine monitoring is programmed to "Shutdown", the warning lamp will continue flashing after the derate mode until the engine is shut down. Refer to Troubleshooting, "System Overview".
Output 1 (PTO Switch On Lamp)
Output 1 is used for the PTO Switch ON Lamp when OCT99 or older software is used. However, the "PTO configuration" must be programmed to "Cab Switches", "Remote Switches", or "Remote Throttle". The PTO Switch ON Lamp should turn on when the circuit for the PTO On/Off Switch is turned on.
With OCT99 and newer software, "Output 1" can be used as a PTO Switch On Lamp output or a Low Coolant Level Warning Lamp output. The customer parameters determine the desired usage. If the "Engine Monitoring Lamps" parameter is programmed to "Option 1" and the "Coolant Level Sensor" parameter is programmed to "4-pin", then "Output 1" is used as a Low Coolant Level Warning Lamp output. Otherwise, "Output 1" can be used as a PTO Switch On Lamp output. With OCT99 and older Software, "Output 1" was the PTO Switch On Lamp.
"Output 9"
With OCT99 and newer Software, the "Output 9" can be used for a High Coolant Temperature Lamp output if the "Engine Monitoring Lamps" parameter is programmed to "Option 1". If the "Engine Monitoring Lamps" parameter is programmed to the "Warning Lamp" option, then "Output 9" is not used.
Electrical Connection of Lamps
One terminal of each lamp must be connected to battery voltage through the vehicle wiring. The other terminal is connected to the ECM at the ECM vehicle harness connector J1/P1 at the following terminals:
- J1/P1:29 (Warning Lamp or Low Oil Pressure Lamp)
- J1/P1:30 (PTO Switch On Lamp or Low Coolant Level Lamp)
- J1/P1:31 (High Coolant Temperature Lamp)
The ECM illuminates the lamp by providing a path to ground.
 | |
| Illustration 1 | g00676476 |
 | |
| Illustration 2 | g00676565 |
Test Step 1. Inspect Electrical Connectors and Wiring
- Thoroughly inspect ECM vehicle harness connector J1/P1, the firewall bulkhead connector, and the suspect terminal for the lamp. Refer to Illustration 2. 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 is associated with the suspect terminal for the lamp.
Refer to Illustration 2.
- Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).
- Check the harness and wiring for abrasion and pinch points from the battery 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 2.
- 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.
STOP
Test Step 2. Check for Normal Operation of the Warning Lamp(s)
- Monitor the check engine lamp. Turn the ignition key switch to the ON position, while the engine is off. The lamp should turn on for five seconds. Then, the lamp should turn off.
The lamp will continue flashing if there is an active diagnostic code. If there is an active diagnostic code, connect the Caterpillar Electronic Technician (ET) in order to read the active diagnostic code. Troubleshoot the problem.
Note: The warning lamp will not turn on until the engine is cranked.
- Connect ET in order to verify that the "Engine Monitoring" has been programmed to "Warning", "Derate", or "Shutdown". If "Engine Monitoring" is programmed to "Off", the warning lamp is not used and the ECM will not turn on the lamp.
The "Engine Monitoring Lamps" parameter must be programmed to "Option 1" in order for the following lamps to function.
- Low Oil Pressure
- High Coolant Temperature
- Low Coolant Level Warning
The lamp for the low coolant level also requires the "Coolant Level Sensor" parameter to be programmed to the "4-pin" option.
While the warning lamp is being observed, start the engine. The warning lamp should turn on for a minimum of two seconds after the engine starts. Then, the warning lamp should turn off. If the lamp remains on, immediately shut down the engine.
- Low Oil Pressure
Expected Result:
The warning lamp turns on and the Warning Lamp turns off per the above description.
Results:
- OK - The lamp appears to operating correctly at this time.STOP
- Not OK - The lamp is not operating correctly.
Repair: Perform the following diagnostic procedure:Use ET to determine if an "Engine Monitoring" condition is causing the lamp to turn on. If an "Engine Monitoring" condition is not present, perform the following diagnostic procedure.
Proceed to Test Step 3.
Test Step 3. Test the Lamp Circuit
 | |
| Illustration 3 | g00676787 |
Vehicle harness connector P1 | |
- Disconnect ECM vehicle harness connector J1/P1.
- Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to both ends of the wire.
- Insert the jumper into the terminal of the suspect lamp of connector P1. The jumper can be inserted into the following terminals in order to test the appropriate lamp circuit:
- P1:31 (High Coolant Temperature Lamp)
- P1:29 (Warning Lamp or Low Oil Pressure Lamp)
- P1:30 (PTO Switch On Lamp or Low Coolant Level Lamp)
- P1:31 (High Coolant Temperature Lamp)
- Connect the other side of the jumper wire to P1:65 (-Battery).
- Turn the ignition key switch to the ON position.
- While the lamp is being watched, insert the jumper wire and remove the jumper wire.
Refer to Illustration 3.
Expected Result:
Result 1 The lamp turns on while the jumper is connected to both sockets. Also, the warning lamp turns off when the jumper is removed from one of the sockets.
Result 2 The lamp does not turn on while the jumper is connected to both sockets.
Result 3 The lamp will stay on while the ECM vehicle harness connector is disconnected.
Results:
- Result 1 - The warning lamp circuit is functioning properly. Proceed to Test Step 4.
- Result 2 - The lamp did not turn on. The vehicle's lamp circuit is not functioning properly. The lamp is probably burned out or there is a problem in the wiring from the cab to either the ECM or the +Battery connection. Repair the lamp circuit or send the vehicle to the OEM dealer for repairs.STOP
- Result 3 -
Repair: Perform the following diagnostic procedure:The circuit between the ECM and the lamp is shorted to chassis ground. Repair the circuit or send the vehicle to the OEM dealer for repairs.
STOP
Test Step 4. Check ECM Operation of the Warning Lamp
| | |
| Illustration 4 | g00676787 |
ECM Breakout T-connector | |
- Disconnect ECM vehicle harness connector J1/P1.
- Insert a 70-Terminal breakout T between the ECM vehicle harness connectors J1 and P1.
- Connect a voltage test lamp probe to terminal 65 (-Battery) and connect the other probe to terminal 52 (Unswitched +Battery) of the breakout T.
- The test lamp should turn on. If the test lamp does not turn on, either the test lamp is faulty or the wiring to the ECM is faulty. Continue with this step if the lamp turns on.
- Leave the voltage test lamp probe connected to terminal 52 (Unswitched +Battery).
- Connect the other probe of the test lamp to the suspect lamp terminal on the breakout T.
Refer to Illustration 4.
- Watch the voltage test lamp. Start the engine. The lamp should turn on for a minimum of two seconds after the engine starts. Then, the lamp should turn off. Immediately turn the engine off if the lamp continues to stay in the ON position. Connect ET in order to determine the cause of the problem.
Expected Result:
The lamp turns on and the warning lamp turns off per the above description.
Results:
- OK - The ECM is operating correctly. There is a problem in the vehicle wiring or the lamp. Repair the vehicle wiring or the lamp, as required.STOP
- Not OK - Temporarily connect a test ECM. Ensure that the "Engine Monitoring" of the test ECM matches the "Engine Monitoring" of the suspect ECM. Check the ECM operation of the Lamp when the test ECM is installed. If the problem is resolved with the test ECM, reconnect the suspect ECM. If the problem returns with the suspect ECM, replace the ECM.STOP