SENSOR GP-PRESSURE 4849881 - Caterpillar

Illustration 2 g01279964
P1 ECM connector
(P1-5) Digital return
(P1-18) Digital return
Illustration 3 g03007020
P2 ECM connector
(P2-29) Digital supply
(P2-65) Left turbocharger turbine inlet temperature
(P2-73) Right turbocharger turbine inlet temperature
Illustration 4 g01159881
Terminal locations at the connectors for the exhaust temperature sensor
(Terminal A) Digital sensor supply
(Terminal B) Digital return
(Terminal C) Signal
Table 2
Troubleshooting Test Steps Values Results
1. Check for Active Codes and Logged Codes
A. Connect Caterpillar Electronic Technician (ET) to the service tool connector.
B. Monitor the diagnostic codes on Cat ET. Check and record any diagnostic codes.
Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
C. Determine if a diagnostic code has occurred several times.
Note: A diagnostic code that is logged several times is an indication of an intermittent problem. Most intermittent problems are the result of a bad connection between a socket and a pin in a connector. There could also be a bad connection between a wire and a terminal.
D. Look for one or more of the following diagnostic codes that are active or logged:
- 1181-3
- 1181-4
- 1181-8
- 1180-3
- 1180-4
- 1180-8
- 2452-8
Codes
Result: A code is not active or logged.
Repair: There may be an intermittent problem in the harness or in a connector. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct procedures for inspecting electrical connectors.
Result: A code is that active or logged.
The ECM detects a problem in one of the circuits for the exhaust temperature sensors.
Proceed to Test Step 2.
2. Check the Digital Supply Voltage at the Sensor Connector
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the suspect sensor at the sensor connector.
C. Restore the electrical power to the ECM.
D. Measure the supply voltage on the harness side of the sensor connector. Measure the voltage between terminal A and terminal B for the suspect sensor.
8.0 0.4 VDC
Result: The supply voltage is not 8.0 0.4 VDC. The supply voltage is not reaching the sensor connector.
Proceed to Test Step 3.
Result: The supply voltage is 8.0 0.4 VDC. The supply voltage is reaching the sensor connector.
Proceed to Test Step 4.
3. Check the Digital Supply Voltage at the ECM
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the J2/P2 and the J1/P1 ECM connectors.
C. Fabricate a jumper wire that is long enough to use as a test lead at the ECM connector. Crimp a connector socket to one end of the jumper wire.
D. Remove the wire for the digital supply from terminal location P2-29. Install the jumper wire into the terminal location.
E. Connect the J2/P2 ECM connector.
F. Restore the electrical power to the ECM.
G. Measure the voltage between the jumper wire that is in terminal P2-29 and P1-5.
Measure the voltage between the jumper wires that are in terminals P2-29 and P1-18.
H. Turn the main disconnect switch to the OFF position.
I. Restore the wiring to the original configuration.
8.0 0.4 VDC.
Result: The supply voltage at the ECM is 8.0 0.4 VDC.
Repair: The supply voltage at the ECM is correct. There is a problem in the wiring between the ECM