JCB Dump Truck 95 Fault Code: Short Circuit To Battery Voltage At Starter Interlock Relay
Short Circuit To Battery Voltage At Starter Interlock Relay · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Fault code 95 means the TCU (transmission control unit) detected a wrong voltage at the output pin controlling the starter interlock relay, a signal pattern that looks like a short circuit to battery voltage. This points to wiring or relay problems around the starter interlock circuit, not a starter motor fault itself.
High severity. The starter interlock relay controls whether the engine is allowed to start, so a wiring fault here can either prevent starting entirely or create an unsafe wiring condition. It should be diagnosed before the truck is put back into regular service, though it is not typically an immediate stop-the-engine emergency if it is already running.
What does JCB Dump Truck error code 95 mean?
Fault code 95 is set when the TCU, the transmission control unit, reads a voltage at the starter interlock relay output pin that does not match what it expects for a normal open or closed circuit. Instead, the voltage pattern looks like the pin is shorted to battery voltage.
The starter interlock relay is part of the safety circuit that only allows the starter motor to engage under the correct conditions, such as the transmission being in a safe position. If the TCU cannot trust the signal at this pin because it is stuck high, it cannot safely confirm the interlock state.
This code is about the wiring and relay for the interlock signal, not a mechanical starter fault. It is an electrical diagnostic code aimed at the cable, connectors, and relay in that specific control path.
Common causes of 95
- A defective cable between the TCU and the starter interlock relay that has come into contact with battery voltage.
- An internal defect inside the starter interlock relay itself.
- A connector pin in this circuit that is connected to battery voltage when it should not be.
How to troubleshoot JCB Dump Truck 95: first checks
- Inspect the cable routing from the TCU to the starter interlock relay for chafing, pinching, or contact with battery-voltage wiring or terminals.
- Check all connectors between the starter interlock relay and the TCU for corrosion, moisture, bent pins, or contact with an unintended power source.
- Measure the resistance of the starter interlock relay to check for an internal short or defect.
- With the key off, visually trace the interlock circuit for any splice or repair point where a battery-voltage wire could be touching the signal wire.
How the code clears
No reset procedure is listed for this code. After repairing the cable, connector, or relay, clear the code with a diagnostic tool and recheck that it does not return during a start attempt.
Frequently asked questions
What does JCB fault code 95 mean?
It means the TCU detected a voltage at the starter interlock relay output pin that looks like a short circuit to battery voltage, rather than the normal signal it expects.
Will fault code 95 stop my dump truck from starting?
It can, since the starter interlock relay is part of the circuit controlling whether the starter motor is allowed to engage. If the TCU cannot trust the signal, it may prevent starting as a safety measure.
What usually causes fault code 95?
JCB lists three causes: a defective cable in contact with battery voltage, an internal defect in the starter interlock relay, or a connector pin connected to battery voltage.
Is fault code 95 an engine problem or an electrical problem?
It is an electrical wiring and relay problem in the starter interlock circuit, not a mechanical engine or starter motor fault.
How do I check the starter interlock relay for this fault?
Check the resistance of the relay itself, and inspect the cable and connectors between the relay and the TCU for signs of contact with battery voltage.
Is there a reset procedure for code 95?
No reset procedure is listed for this code. Repair the underlying wiring or relay issue, then clear the fault and confirm it does not reset on the next start attempt.