CAT 14 Fault Code: Med/High Retarder current high
Med/High Retarder current high · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
CAT fault code 14, SPN 1073 FMI 6, means the ECM detected a high current condition (short circuit) for one second while trying to energize the solenoids for cylinders 1, 2, 5, and 6, with the engine retarder switch in the medium or high position. It applies to C11, C13, and C15 engines and points to a short in the retarder solenoid circuit or a failed component in that circuit.
Medium severity. This code affects the engine retarder function, not the base brakes, but a shorted retarder circuit can disable engine braking on grades. It should be diagnosed before the vehicle is run in hilly terrain or under heavy load where retarder braking is expected.
What does CAT error code 14 mean?
CAT fault code 14, SPN 1073 FMI 6, is set by the Engine Control Module (ECM) when it tries to energize the retarder solenoids for cylinders 1, 2, 5, and 6 and instead sees a high current condition, which the ECM reads as a short circuit. This happens specifically while the engine retarder switch is set to the medium or high position.
The engine retarder uses engine compression braking to slow the vehicle without relying only on the wheel brakes. CAT installs the retarder solenoids on the engine, but the truck manufacturer installs the retarder switch, so the fault can originate on either the engine side or the vehicle side of the wiring.
Because the fault is tied to a short circuit in the solenoid drive circuit, it usually means current is finding an unintended path to ground or to another circuit somewhere between the ECM and the valve cover connector, or further out into the cab wiring.
What triggers a CAT 14 code?
The ECM sets this code when it detects a high current (short circuit) condition for one second while attempting to energize the cylinder 1, 2, 5, and 6 retarder solenoids, and only while the engine retarder switch is in the medium or high position.
Common causes of 14
- Short at the wiring for the brake retarder solenoid at the valve cover connector
- ECM failure
- ECM connection harness fault
- Engine retarder solenoid failure
- Harness fault between the connector for the engine retarder and the valve cover connector
- Vehicle harness fault in the cab
- Harness fault between the ECM and the firewall bulkhead connector
- ECM programmed improperly
- Accelerator pedal position sensor or its harness
- Clutch pedal position sensor or its harness
- Mechanical failure with the engine retarder itself
How to troubleshoot CAT 14: first checks
- Inspect the wiring and connector at the valve cover for chafing, pinched wires, or corrosion that could cause a short to ground.
- Check the harness routing between the engine retarder connector and the valve cover connector, and between the ECM and the firewall bulkhead connector, for damage.
- Inspect the vehicle harness in the cab, since the retarder switch is installed by the truck manufacturer and cab wiring is a common wear point.
- Check the accelerator pedal position sensor and clutch pedal position sensor along with their harnesses, since these are listed as possible contributors.
- Verify the ECM connection harness is seated properly and free of corrosion at the connector pins.
- Confirm the ECM programming matches the vehicle and engine retarder configuration.
- Inspect the engine retarder solenoid itself and the retarder mechanism for a mechanical failure if wiring checks come back clean.
How the code clears
No separate clearing step is listed for this code. Diagnosis should focus on locating the short circuit in the retarder solenoid wiring path, from the valve cover connector back through the engine harness, vehicle cab harness, and ECM connections, then repairing or replacing the failed component before expecting the code to clear on its own after the fault condition is resolved.
Affected models and serial ranges
14 appears in our records across 3 CAT models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| C11 | Serial range not listed in source records |
| C13 | Serial range not listed in source records |
| C15 | Serial range not listed in source records |
Frequently asked questions
What does CAT fault code 14 mean?
It means the ECM detected a high current, short circuit condition for one second while trying to energize the retarder solenoids for cylinders 1, 2, 5, and 6, with the retarder switch in the medium or high position. This is SPN 1073 FMI 6 on C11, C13, and C15 engines.
Can I still drive with fault code 14 active?
The base wheel brakes are not affected, but the engine retarder function tied to the medium/high switch position may not work. If you rely on engine braking on grades, get this diagnosed before heavy downhill or loaded driving.
Is fault code 14 an engine problem or a truck wiring problem?
It can be either. CAT installs the retarder solenoids on the engine, but the truck manufacturer installs the retarder switch and related cab wiring, so the short can be on either side of that boundary.
What usually causes a retarder current high fault?
The most commonly cited cause is a short at the wiring or connector near the valve cover, but it can also be an ECM failure, a harness fault anywhere between the ECM and the retarder solenoid, a bad accelerator or clutch pedal position sensor, or a mechanical failure in the retarder itself.
Does fixing fault code 14 require an ECM replacement?
Not usually. ECM failure or improper ECM programming are listed as possible causes, but wiring and connector issues at the valve cover, harness, and cab level are also on the list and should be checked first since they are more common and cheaper to fix.
Will this code clear itself after I fix the wiring?
No separate clearing step is listed. Once the short circuit is repaired, the ECM should stop detecting the high current condition on the next attempt to energize the solenoids.