ELBOW-EXHAUST 4N4352 - Caterpillar

System Operation Description:Use this procedure to troubleshoot diagnostic codes for open circuits or short circuits for the sensors of these parameters:
Engine coolant temperature
Inlet air temperature
Engine oil temperature
Filtered engine oil pressure
Unfiltered engine oil pressureNote: The engine coolant temperature sensor does not require +5 VDC from the Electronic Control Module (ECM). The engine coolant temperature sensor is a passive sensor of the analog type. The sensor operates without a voltage supply from the ECM.The ECM can be configured for one of these types of speed control:
Potentiometer
4-20 maThe "DESIRED SPEED" potentiometer (if equipped) must be supplied with +5 VDC from the ECM. If the "DESIRED SPEED" potentiometer has a short circuit or the potentiometer's wiring has a short circuit, a 262-03 or 262-04 diagnostic code may be activated. There are no diagnostic codes for the circuit of the "DESIRED SPEED" potentiometer.An -03 code is probably caused by a problem in an engine harness. There may be an open circuit in a harness, or a short circuit to a positive voltage source in a harness. The next likely cause is a sensor problem. The least likely cause is a problem with the ECM.An -04 code is probably caused by a short circuit to ground in an engine harness. The next likely cause is a sensor problem. The least likely cause is a problem with the ECM.Logged diagnostic codes provide an historical record. Before you begin this procedure, use the Caterpillar Electronic Technician (ET) to print the logged codes to a file.This troubleshooting procedure may generate additional diagnostic codes. Keep your mind on correcting the cause of the original diagnostic code. Clear the diagnostic code after the problem is resolved.
Illustration 1 g01078407
Schematic for the analog sensorsTest Step 1. Inspect the Electrical Connectors and Wiring
Illustration 2 g01071294
Terminal box (1) ECM connectors J1/P1 (2) J12/P12 connectors for the analog sensors (3) 16 amp circuit breaker
Set the engine control to the OFF/RESET mode. Switch 16 amp circuit breaker (3) to the OFF position.Note: For the following steps, refer to Troubleshooting, "Inspecting Electrical Connectors".
Thoroughly inspect the following connectors:
J1/P1 connectors
J12/P12 connectors on the terminal box
Check the torque of the allen head screw for the ECM connector. The proper torque is 6 1 N m (55 9 lb in).
Illustration 3 g01071300
Harness side of the P1 connector (P1-2) 5 volt supply (P1-3) Return (P1-14) Signal for the inlet manifold air temperature (P1-17) Signal for the engine oil temperature (P1-24) Signal for the filtered engine oil pressure (P1-26) Signal for the unfiltered engine oil pressure (P1-27) Signal for the engine coolant temperature
Illustration 4 g00889763
Harness side of the P12 connector (P12-A) 5 volt supply (P12-C) Return (P12-E) Signal for the unfiltered engine oil pressure (P12-F) Signal for the filtered engine oil pressure (P12-H) Signal for the engine oil temperature (P12-J) Signal for the engine coolant temperature (P12-K) Signal for the inlet manifold air temperature
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the analog sensors.
Illustration 5 g01071307
Right side view (4) Inlet air temperature sensor