High Side Driver Failure
Issue with the high side driver circuit for a component.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
There's a problem with the electrical circuit that powers a component, which could prevent it from working.
What the computer is actually seeing
The engine computer detects a voltage outside of normal ranges from the high side driver, usually above 1.5V or below 0.1V when it should be active.
What a healthy reading looks like
When active, the expected voltage from the high side driver should be between 2.5V and 12V; under normal conditions, it should be around 5V.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the wiring and connectors for damage or corrosion. Repair any issues found. Decision: If damaged, repair and retest.
- 22. Measure the voltage at the high side driver connector with the engine running. Decision: If measured voltage is outside the expected values, proceed to step 3.
- 33. Disconnect the high side driver module and measure resistance across the connector terminals. Decision: If resistance is above specifications, replace the driver module.
- 44. Check for shorts to ground or other power sources in the circuit. Decision: If a short is found, repair the circuit before retesting.
Common causes
- Damaged wiring or connectors in the high side driver circuit
- Faulty high side driver module
- Short circuit to ground or positive voltage from another source
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with SPN 238 active?
No, this code often indicates a critical component may not be functioning, potentially leading to engine failure or unsafe operation.
Will this code come back after clearing it?
If the underlying issue isn't fixed, yes, the code will likely return.
Why is this code linked with other SPN codes?
These codes often share wiring or components, so a fault in one can impact others.
Working a real vehicle right now?
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