Undervoltage error Lexus IS

I've got a 2005 Lexus IS diesel that's throwing me a curveball. It's done 245993 km. I'm getting an 'error stored in the error memory' message, and the fault memory seems to be locked. Could this be undervoltage like I suspect, or am I barking up the wrong tree?

4 comment(s)

Undervoltage, you say? Interesting. Have you checked the battery's condition and the charging system output? What fault codes are you pulling, if any? Is the car exhibiting any other symptoms beyond the error message?

I haven't checked the charging system output, admittedly. I was leaning towards undervoltage as a potential cause, as I've heard it can cause the ECU to act up. What voltage levels should I be looking for when testing the battery and charging system?

Given the mileage and the undervoltage suspicion, it is advisable to have the battery and alternator professionally tested. Considering the fault memory lock, a visit to a trusted automotive workshop equipped with advanced diagnostics would be most prudent at this stage to prevent further complications.

Thanks for the advice! Took it to a workshop, and you nailed it - turns out there was indeed an undervoltage issue. A new voltage regulator, and a diagnostic check cost me 240€. All sorted now!

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