Applicable Systems
EMCP 4.2
Symptoms
ECM output driver signal erratic; specific output may not activate reliably; intermittent component operation.
Possible Causes
- ECM internal output driver degradation
- Output circuit short to ground intermittent
- ECM connector pin corrosion
Troubleshooting Steps
- Step 1: Check ECM connector for corroded pins
Connector pins clean - Step 2: Monitor affected output with Cat ET
Output activates consistently - Step 3: Check output wiring for intermittent shorts
No shorts found - Step 4: If ECM driver faulty, replace ECM
New ECM outputs stable - Step 5: Clear code and verify all outputs
All outputs function correctly
How to Reset
Clear via Cat ET after ECM service.
Common Replacement Parts
- Engine ECM (model specific)
Frequently Asked Questions
- Q: Can ECM output drivers be repaired?
No. Internal output drivers are part of ECM circuit board. Failed driver requires complete ECM replacement and programming.
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Source: caterpillarfaultcodes.com CID list
Category: Heavy Equipment
Published: 2026-10-12
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