P1374 Engine Temp Light Monitor Circuit
The P1374 code indicates a fault in the engine temperature warning light monitor circuit, specific to General Motors vehicles. The Powertrain Control Module (PCM) continuously checks the feedback circuit that verifies the temperature warning light on the instrument cluster illuminates when commanded. If the PCM does not receive the expected confirmation signal, it sets this code. This is a medium-severity issue that can affect the driver's ability to detect engine overheating.
01. Most Common Causes
- Burnt-out or missing engine temperature warning light bulb
- Open or short circuit in the light feedback circuit
- Faulty instrument cluster
- Loose or corroded connections in the light circuit harness
- Internal PCM failure in the monitoring circuit
- Incorrect resistance in the bulb circuit
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine temperature warning light may not illuminate during bulb check or when overheating
03. Step-by-Step Diagnosis
Scan for codes and verify P1374 is present
Inspect the engine temperature warning light bulb and replace if burned out
Check the feedback circuit wiring for opens, shorts, or corrosion
Test the instrument cluster function and connections
Measure circuit resistance and compare to specifications
If all else fails, test PCM output and consider PCM replacement
1. Frequently Asked Questions
Is it safe to drive?▼
You can drive short distances, but the loss of the temperature warning light increases the risk of engine damage from overheating. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
Repair costs range from $50 for a simple bulb replacement to $500 or more if the instrument cluster or PCM needs replacement.