P1680 IDM Enable Circuit Malfunction
The P1680 code indicates a fault in the Injection Driver Module (IDM) enable circuit, specific to Ford Power Stroke diesel engines, particularly the 7.3L. The IDM controls the high-pressure injectors in the HEUI system. The IDM_EN signal is an enable line that allows the module to operate; when this signal fails, the PCM detects an interruption or anomaly in the IDM control circuit, preventing proper injector activation and causing starting or running issues.
01. Most Common Causes
02. Symptoms You Will Notice
- Engine cranks but won't start
- Engine starts but runs rough or stalls
03. Step-by-Step Diagnosis
Check for blown fuses in the IDM power circuit
Inspect the IDM connector for corrosion, loose pins, or damage
Test the IDM_EN circuit for continuity and resistance between PCM and IDM
Verify IDM ground connection is clean and tight
If all else fails, test the IDM and PCM for internal faults
1. Frequently Asked Questions
Is it safe to drive?▼
No, this is a high-severity fault. The vehicle may stall or fail to start, posing a safety risk. Have it diagnosed immediately.
How much does it cost to fix?▼
Repair costs range from $100 for a blown fuse or wiring repair to $800+ for IDM or PCM replacement, including labor.