Applicable Systems
EMCP 4.2
Symptoms
The EMCP 4.2 reports fault 164-2 for the Injector Actuation Pressure circuit where the data is erratic, intermittent, or incorrect. This indicates a loose connection or signal noise rather than a hard short.
Possible Causes
- IAP sensor connector partially disconnected or corroded
- Signal wire intermittent open circuit due to harness flex
- Sensor internal element failing intermittently with temperature
- Ground loop or electrical noise on sensor signal line
Troubleshooting Steps
- Step 1: Check EMCP fault log for intermittent 164-2 pattern
Fault appears and clears intermittently during operation - Step 2: Inspect IAP sensor connector for corrosion, loose pins, or incomplete seating
Connector clean, fully seated with locking tab engaged - Step 3: Wiggle test the wiring harness from sensor to ECM while monitoring EMCP
No fault transitions observed during harness manipulation - Step 4: Replace IAP sensor if intermittent fault persists after connector service
Fault no longer appears after sensor replacement
How to Reset
To reset: 1) Repair the intermittent connection or replace sensor. 2) Press FAULT RESET on EMCP. 3) Press AUTO.
Frequently Asked Questions
- Q: Why does fault 164-2 come and go?
FMI 2 faults are typically caused by intermittent connections, vibration-induced opens, or temperature-dependent sensor failures. The signal is sometimes valid, sometimes not.
- Q: Can weather affect this fault?
Yes. Temperature changes can cause connector expansion/contraction, and moisture can create intermittent conductivity paths. Seasonal occurrence is common.
Source: Caterpillar EMCP 4.2 Operation & Maintenance Manual (LERMPMM), caterpillarfaultcodes.com CID-FMI Reference
Category: Generator