System Operation Description:
The following background information is related to the following procedure:
A warning lamp is required for the “Engine Monitoring” feature. 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. Three warning lamps may be used for the “Engine Monitoring” feature. The “Engine Monitoring Lamps” parameter must be programmed to reflect the number of warning lamps that are used.
Warning Lamp Programming the “Engine Monitoring Lamps” parameter to “Warning Lamp” requires only one lamp. The lamp will display warnings for oil pressure, coolant level, and coolant temperature.
Option 1 Programming the “Engine Monitoring Lamps” parameter to “Option 1” requires three lamps. P1:29 (Warning Lamp) is connected to the lamp for low oil pressure. P1:30 (Output #1) is connected to the lamp for low coolant level. P1:31 (Output #9) is connected to the lamp for high coolant temperature.
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”.
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.
Test Step 1. Inspect Electrical Connectors and Wiring
A. Thoroughly inspect the J1/P1 ECM connector, the firewall bulkhead connector, and the suspect terminal for the lamp. Refer to Illustration 198.
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 is associated with the suspect terminal for the lamp.
Refer to Illustration 198.
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 battery to the ECM.
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.
• 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.
Test Step 2. Check for Normal Operation of the Warning Lamp(s)
A. 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 (Cat 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.
B. 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 or the “2 wire Float Sensor” 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.
The warning lamp turns on and the Warning Lamp turns off per the above description.
• OK – The lamp appears to operating correctly at this time. STOP.
• Not OK – The lamp is not operating correctly.
Repair: Perform the following diagnostic
Use Cat 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
A. Disconnect the J1/P1 ECM connector.
B. Fabricate a jumper wire 100 mm (4 inch) long.
Crimp a Deutsch pin to both ends of the wire.
C. 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)
D. Connect the other side of the jumper wire to P1:65 (-Battery).
E. Turn the ignition key switch to the ON position.
F. While the lamp is being watched, insert the jumper wire and remove the jumper wire. Refer to Illustration 199.
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.
• 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
A. Disconnect the J1/P1 ECM connector.
B. Insert a breakout T between the J1 and P1 ECM connectors.
C. Connect a voltage test lamp probe to terminal 65 (-Battery) and connect the other probe to terminal 52 (Unswitched +Battery) of the breakout T.
D. 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.
E. Leave the voltage test lamp probe connected to terminal 52 (Unswitched +Battery).
F. Connect the other probe of the test lamp to the suspect lamp terminal on the breakout T.
Refer to Illustration 200.
G. 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 Cat ET in order to determine the cause of the problem.
The lamp turns on and the warning lamp turns off per the above description.
• 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.