DTC 112 — Electrical System B+ Voltage Out of Range – High — International DT466E

DTC 112 on the International DT466E (1996–2003) indicates the ECM is seeing battery voltage above its valid range. The code is a Navistar three-digit flash…

Updated October 15, 2026

What it means

On the International DT466E (1996–2003) Navistar three-digit system, DTC 112 means the battery voltage at the ECM is above its valid range. The affected system is the charging system. Typical on this platform: usually an overcharging alternator/regulator or a jump-start with too high a voltage.¹

Most likely causes

1. Overcharging alternator or voltage regulator — Alternator output exceeds the ECM’s high-voltage threshold, causing the ECM to set DTC 112. Check alternator output and regulator operation under load and at idle.¹
2. Jump-start or external power source with excessive voltage — Connecting a jump pack or charger that supplies voltage above the ECM’s valid range can set the code. Verify source voltage before connecting and retest after normal power is restored.¹
3. Charging circuit wiring fault raising ECM B+ sense voltage — Corrosion, damaged insulation or a short that raises the voltage sensed at the ECM B+ input can trigger the code. Inspect ECM power and ground circuits, fusible links and connections for damage or contamination.¹

How to diagnose

1. Verify the code with a scan tool or flash-code read and record freeze-frame conditions.
2. Measure battery voltage at the battery posts with engine off and running; compare to ECM-reported B+ voltage.
3. Inspect alternator output and regulator function; look for overcharge condition and test with a load tester.
4. Check for recent jump-start or external charger use and confirm supply voltage was within limits.
5. Inspect ECM power/ground circuits, fusible links, connectors and wiring for corrosion, damage or shorts that could raise sensed B+ voltage.
6. Clear codes, run engine through normal operating range and confirm DTC 112 does not return.

Specs and test values

Parts and tools you may need

• Digital multimeter
• Battery load tester
• Alternator tester
• Navistar-compatible scan tool or flash-code reader
• Basic hand tools and wiring inspection supplies

Tools you’ll need

• digital multimeter — Measures battery and ECM B+ voltage at the posts and at the ECM to confirm over-voltage and compare to ECM-reported values.
• OBD-II scan tool — Reads DTC 112 and freeze-frame data on the DT466E to verify the code and monitor ECM-reported B+ voltage during operation.
• alternator load tester — Tests alternator output and regulator function under load to identify an overcharging condition causing ECM voltage to exceed range.
• battery load tester — Checks battery condition and verifies system voltage stability after jump-starts or external charging to rule out supply-related over-voltage.

Rough cost and difficulty

Typical US independent-shop figures; labor runs about $140–$200 per hour (dealers charge more). Confirm the diagnosis before buying parts.

When to see a pro

If voltage remains high after alternator/regulator replacement, or if ECM power/ground wiring faults are suspected, have a qualified diesel technician perform pinpoint electrical tests to avoid ECM damage. Stop diagnosis if high voltage persists and seek professional service.

Check for recalls

Recalls are tied to your truck’s VIN, so check yours directly: enter the VIN at NHTSA’s recall lookup. Open safety recalls are repaired free at a dealer.

Sources