0392935 JOHNSON UPPER HOUSING & FUEL LINE ASSY.

Table 1
Diagnostic Codes Table
Code Conditions which Generate this Code System Response
1501-3 Cylinder #1 Detonation Sensor : Voltage Above Normal
1502-3 Cylinder #2 Detonation Sensor : Voltage Above Normal
1503-3 Cylinder #3 Detonation Sensor : Voltage Above Normal
1505-3 Cylinder #5 Detonation Sensor : Voltage Above Normal
1506-3 Cylinder #6 Detonation Sensor : Voltage Above Normal
1507-3 Cylinder #7 Detonation Sensor : Voltage Above Normal
1509-3 Cylinder #9 Detonation Sensor : Voltage Above Normal
1510-3 Cylinder #10 Detonation Sensor : Voltage Above Normal
1513-3 Cylinder #13 Detonation Sensor : Voltage Above Normal
1514-3 Cylinder #14 Detonation Sensor : Voltage Above Normal The run relay and the crank terminate relay are energized. The input of a signal from a detonation sensor to the Electronic Control Module (ECM) is greater than 4.8 VDC for ten seconds. The shutdown output is activated. The code is logged.
The engine is shut down.
Table 2
Diagnostic Codes Table
Code Conditions which Generate this Code System Response
1501-4 Cylinder #1 Detonation Sensor : Voltage Below Normal
1502-4 Cylinder #2 Detonation Sensor : Voltage Below Normal
1503-4 Cylinder #3 Detonation Sensor : Voltage Below Normal
1505-4 Cylinder #5 Detonation Sensor : Voltage Below Normal
1506-4 Cylinder #6 Detonation Sensor : Voltage Below Normal
1507-4 Cylinder #7 Detonation Sensor : Voltage Below Normal
1509-4 Cylinder #9 Detonation Sensor : Voltage Below Normal
1510-4 Cylinder #10 Detonation Sensor : Voltage Below Normal
1513-4 Cylinder #13 Detonation Sensor : Voltage Below Normal
1514-4 Cylinder #14 Detonation Sensor : Voltage Below Normal
1515-4 Cylinder #15 Detonation Sensor : Voltage Below Normal
1516-4 Cylinder #16 Detonation Sensor : Voltage Below Normal The run relay and the crank terminate relay are energized. The input of the signal from the detonation sensor to the ECM is less than 1.0 VDC for ten seconds. The shutdown output is activated. The code is logged.
The engine is shut down. Detonation sensors are located on the upper cylinder block between every two cylinders. Each sensor monitors two adjacent cylinders. For example, one sensor monitors cylinders 1 and 3.The ECM supplies 8 VDC in order to power the sensors. The detonation sensors provide electrical signals to the ECM that indicate mechanical engine vibrations. Each sensor outputs an electrical signal that is filtered and the signal is amplified. The frequency of the signal corresponds to the mechanical frequency of the vibrations. The amplitude of the signal is proportional to the intensity of the vibrations.The ECM monitors the signals in order to determine the presence and the severity of the detonation. The ECM retards the timing in order to limit detonation levels. The timing may be retarded for a single cylinder or for all of the cylinders, if necessary. If retardation of the timing does not sufficiently limit the detonation, the engine is shut down.The ECM can retard timing by as few as three degrees for light detonation levels. The timing can be retarded up to six degrees for severe detonation. For most applications, the minimum allowable actual timing is ten degrees Before Top Center (BTC). A proportional strategy is used for advancing the timing after the timing has been retarded. The rate of advance is based upon the level of detonation. The rate is faster for lighter detonation. The fastest rate of advance is one degree per minute.The ECM will diagnose the detonation sensor's signal for a short circuit to the −Battery side, for a short circuit to the +Battery side, and for an open circuit. To avoid detecting vibrations that are not related to detonation, the ECM only monitors a detonation sensor when one of the sensor's cylinders is between top center and 40 degrees after top center.An input from a detonation sensor that is diagnosed by the ECM as "short to ground" may actually indicate an open circuit.The ECM also supports event codes when the levels of detonation warrant a reaction from the ECM. If the timing has been retarded by the maximum amount and the level of detonation remains high, the ECM will shut down the engine.Logged diagnostic codes provide a historical record. Before you begin this procedure, use Caterpillar Electronic Technician (ET) to print the logged codes to a file.The most likely causes of the diagnostic code are a poor connection or a problem in a wiring harness. The next likely cause is a problem with a sensor. The least likely cause is a problem with the ECM.The troubleshooting procedure may generate additional diagnostic codes. Keep your mind on correcting the cause of the original diagnostic code. Clear the diagnostic codes after the problem is resolved.
Illustration 1 g01442392
Schematic for the detonation sensors on vee engines
The wiring for the detonation sensors is routed through rails on each side of the engine. Each detonation sensor has a 3-pin connector that is connected to a receptacle on the rail.
Each rail has a 6-pin connector for a wiring harness that connects the detonation sensors to the terminal box.
Illustration 2 g01442393
Schematic for the detonation sensors on in-line engines
The wiring for the detonation sensors is routed through a rail on the side of the engine. Each detonation sensor has a 3-pin connector that is connected to a receptacle on the rail.
The rail has a 6-pin connector for a wiring harness that connects the detonation sensors to the terminal box.
Test Step 1. Inspect the Electrical Connectors and Wiring
Illustration 3 g01431198
Terminal Box
(1) ECM connector J2/P2
(2) ECM connector J1/P1
(3) 16 amp circuit breaker
(4) Connectors J3/P3 for the customer's connector
(5) Connectors J4/P4 for the optional control panel (if equipped) or for a customer's connector
(6) J5/P5 connectors for the harness
(7) J6/P6 connectors for the harness
Turn the engine control switch to the OFF/RESET position. Switch the 16 amp circuit breaker for the ECM OFF. Note: For the following steps, refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 4 g01442541
Connectors on the rail for in-line engines
(8) Rail on the right side of the engine
(9) 6-pin connectors J675/P675 for the engine harness
(10) Connectors on the rail for the detonation sensor
(11) Detonation sensor