Caterpillar 3126B troubleshooting: 35 fault codes and 6 symptom-cause-remedy entries from the manufacturer's own service documentation.
Caterpillar 3126B — full specs, parts & maintenance.
| Code | Meaning | Remedy |
|---|---|---|
| 13 | Fault for the Fuel Temperature Sensor | |
| 15 | Open or Short Circuit of Injection Actuation Pressure Sensor | |
| 17 | High Injection Actuation Pressure | |
| 18 | Open or Short for the Injection Actuation Pressure Control Valve | |
| 21 | Sensor Supply Voltage Above Normal or Below Normal | |
| 24 | Oil Pressure Sensor Fault | |
| 25 | Inlet Manifold Air Pressure Sensor Fault | |
| 26 | Atmospheric Pressure Sensor Fault | |
| 27 | Coolant Temperature Sensor Fault | |
| 28 | Check the Adjustments for the Throttle Position Sensor. | |
| 34 | Loss Of Engine RPM Signal | |
| 35 | Event for Engine Overspeed | |
| 37 | Fuel Pressure Sensor Fault | |
| 38 | Inlet Manifold Air Temperature Sensor Fault | |
| 39 | Mechanical Failure of the Injection Actuation Pressure Sensor | |
| 42 | Check the Calibration of the Timing Sensor. | |
| 46 | Low Oil Pressure Event | |
| 51 | Intermittent Battery Power to the ECM | |
| 52 | Personality Module Fault | |
| 56 | The following parameters must be checked: Customer and System | |
| 59 | Incorrect Engine Software | |
| 61 | Event for High Coolant Temperature | |
| 62 | Event for Low Coolant Level | |
| 63 | Low Fuel Pressure Event | |
| 64 | Event for High Inlet Manifold Air Temperature | |
| 65 | Event for High Fuel Temperature | |
| 72 | Fault of Cylinder 1 or Cylinder 2 | |
| 73 | Fault of Cylinder 3 or Cylinder 4 | |
| 74 | Fault of Cylinder 5 or Cylinder 6 | |
| i01463504 | Fault Logging | The system provides the capability of Fault Logging. When the Electronic Control Module (ECM) generates an active diagnostic code, the code will be logged in the memory of the ECM. |
| i01324374 | Engine Operation with Active Diagnostic Codes | If the diagnostic lamp starts to flash codes during normal engine operation, the system has identified a situation that is not within the specification. Use Caterpillar electronic service tools to check the active diagnostic codes. |
| i01456915 | Engine Operation with Intermittent Diagnostic Codes | If the diagnostic lamp starts to flash codes during normal engine operation and the diagnostic lamp shuts off, an intermittent fault may have occurred. If a fault has occurred, the fault will be logged into the memory of the Electronic Control Module (ECM). |
| i01324368 | An intermittent failure in the TPS causes the engine speed to vary erratically. | |
| Diagnostic Flash Code | The “DIAGNOSTIC” lamp flashes in order to indicate a two-digit code. | |
| i01462046 | Engine Stopping | Stop the engine according to the procedure in the Operation and Maintenance Manual, “Engine Stopping (Operation Section)” in order to avoid overheating of the engine and accelerated wear of the engine components. Use the Emergency Stop Button (if equipped) ONLY in an emergency situation. Do not use the Emergency Stop Button for normal engine stopping. After an emergency stop, DO NOT start the engine until the problem that caused the emergency stop has been corrected. |
| Symptom | Cause | Remedy |
|---|---|---|
| Occasional starting problem | Low battery charge | |
| Occasional starting problem | Lack of fuel | If the engine fuel system has been run dry, fill the fuel tank and prime the fuel system. |
| Occasional starting problem | Problem with the wiring harness | Check the connectors in order to ensure that the connectors are secure; lightly pull each of the wires in the chassis harness; if a wire is loose, push the wire back into the connector and pull the wire again in order to ensure that the wire is secure; start the engine. If the engine does not start, consult the nearest Caterpillar dealer for assistance. |
| Overspeed condition during initial start-up or overhauled engine | Stop the engine by shutting off the fuel supply to the engine and/or shutting off the air supply to the engine. | |
| Loose or frayed electrical wires | Check the electrical wires daily for wires that are loose or frayed. Tighten all loose electrical wires before the engine is started. Repair all frayed electrical wires before the engine is started. See the Operation and Maintenance Manual for specific starting instructions. | |
| Improper grounding | Proper grounding for the engine electrical system is necessary for optimum engine performance and reliability. Improper grounding will result in uncontrolled electrical circuit paths and in unreliable electrical circuit paths. Uncontrolled electrical circuit paths can result in damage to main bearings, to crankshaft bearing journal surfaces, and to aluminum components. Engines that are installed without engine-to-frame ground straps can be damaged by electrical discharge. To ensure that the engine and the engine electrical systems function properly, an engine-to-frame ground strap with a direct path to the battery must be used. This path may be provided by way of a direct engine ground to the frame. All grounds should be tight and free of corrosion. The engine alternator must be grounded to the negative “-” battery terminal with a wire that is adequate to handle the full charging current of the alternator. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Documented causes: Low battery charge; Lack of fuel; Problem with the wiring harness. See the table for the matching fixes.