Applicable Systems
EMCP 4.2
Symptoms
Engine RPM does not match throttle input; throttle response sluggish or jerky; possible idle fluctuation.
Possible Causes
- Throttle position sensor wiper track wear
- Sensor connector loose
- Throttle linkage binding
Troubleshooting Steps
- Step 1: Monitor throttle position sensor voltage on Cat ET
Voltage sweeps smoothly 0.5-4.5V - Step 2: Check sensor connector for loose terminals
Connector fully seated - Step 3: Inspect throttle linkage for binding/sticking
Linkage moves freely - Step 4: Replace throttle position sensor if signal erratic
New sensor signal smooth - Step 5: Clear code and calibrate throttle via Cat ET
Throttle calibration successful
How to Reset
Clear via Cat ET; requires throttle calibration after replacement.
Common Replacement Parts
- Throttle Position Sensor P/N: 279-9831
Frequently Asked Questions
- Q: How to calibrate throttle position sensor?
Use Cat ET: go to Service > Calibration > Throttle Position Sensor. Follow on-screen prompts. Engine must be at operating temp.
Source: caterpillarfaultcodes.com CID list
Category: Heavy Equipment