Engine Coolant Temperature High - Warning
What does CUMMINS-146 mean?
The CUMMINS-146 (Cummins) diesel fault code means: Engine Coolant Temperature High - Warning. This is a moderate severity code.
Common Symptoms
- Engine temperature or pressure abnormal
- Possible engine derate or shutdown
- Dash warning lamp illuminated
- Gauges reading outside normal range
- Audible engine change (knock, ticking, or hiss)
- Overheat warning alarm sounding
Probable Causes (Ranked by Likelihood)
- Actual mechanical issue (low oil, coolant, temp) Very Likely
- Failed sensor falsely reporting Likely
- Cooling system issue (fan, radiator, pump) Possible
- Head gasket or combustion gas leak Possible
- Obstructed airflow at charge air cooler Less Likely
Step-by-Step Diagnostic Procedure
Verify the physical condition indicated by fault 146 -- for temperature codes, confirm with an IR thermometer; for pressure codes, use a mechanical gauge.
Compare mechanical reading to sensor reading on INSITE -- if they disagree, sensor or wiring is faulty.
Inspect the mechanical system (cooling, oil, fuel supply) for the underlying issue reported by the sensor.
Check engine fan operation, coolant level, and radiator condition for temp-related codes.
If mechanical reading confirms the fault, repair the underlying system before clearing codes -- clearing without fix will cause fault return and potential engine damage.
Frequently Asked Questions
What is Cummins fault code 146?
Cummins fault code 146 indicates: Engine Coolant Temperature High - Warning. It is a moderate-severity fault affecting engine mechanical condition.
Can I drive with Cummins fault code 146?
Short-term, yes, but the engine will enter derate (typically starting at 55 mph and progressing to 5 mph for emissions faults). Drive directly to a repair facility. Do not defer this fault more than a few operating hours.
How much does it cost to fix Cummins fault 146?
Repair cost is approximately $150-$1,200 including parts, labor, and any dealer programming required. DIY repairs (sensor replacement) fall at the low end; pump, aftertreatment, or ECM work falls at the high end and usually requires INSITE diagnostic software.