Applicable Systems
EMCP 4.2
Symptoms
Coolant temperature signal erratic; temperature display may jump or read maximum; possible false overheating warning.
Possible Causes
- Coolant temp sensor signal intermittent
- Sensor connector water intrusion
- Sensor ground circuit high resistance
Troubleshooting Steps
- Step 1: Check coolant temp sensor resistance vs temperature chart
Resistance matches chart - Step 2: Inspect sensor connector for moisture
Connector dry and clean - Step 3: Check sensor ground circuit resistance
Ground < 1 ohm - Step 4: Replace coolant temp sensor if signal erratic
New sensor signal stable - Step 5: Clear code and verify temperature reading stable
Temp stable at 85-95C
How to Reset
Clear via Cat ET after sensor replacement.
Common Replacement Parts
- Coolant Temperature Sensor P/N: 213-9510
Frequently Asked Questions
- Q: What causes erratic temperature readings?
Most commonly connector moisture/corrosion or sensor internal failure. Always check connector before replacing sensor.
Source: verizonconnect.com DTC guide
Category: Heavy Equipment