P068A
PowertrainECM/PCM Power Relay De-Energized Too Early
Most of the time this comes down to a tired PCM power relay with worn internal contacts, or a battery and connection that's letting voltage sag at the wrong moment. The ECU expects its main power relay to stay energised for a set period after you switch off, so it can finish writing data and run its housekeeping. If that relay drops out early, the module flags P068A because it didn't get the time it needed to shut down cleanly.
ⓘ Information only. This page provides general educational information about fault code P068A. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P068A mean?
P068A is a Powertrain (engine, transmission, fuel system) fault code. It indicates: ECM/PCM Power Relay De-Energized Too Early.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine warning light on the dash, sometimes the only thing you'll notice
- • Intermittent no-start, often after the car has sat overnight
- • Slow or lazy cranking, or just a click from the starter with no turnover
- • Car drops into limp mode with reduced power and some functions switched off
- • Other fault codes stored at the same time, since a power glitch can upset several modules at once
- • Occasional dead dash on key-on before everything wakes up properly
Possible causes
Causes commonly associated with P068A, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Worn PCM power relay with pitted or burnt internal contacts. This is where I'd put my money first, especially on higher-mileage cars
- 2. Loose or corroded battery terminals dropping voltage for a fraction of a second during shutdown, which is enough to trip it
- 3. Weak or failing battery sagging below threshold, common on cars that do mostly short trips
- 4. Damp or corrosion in the under-bonnet fuse box getting into the relay socket pins
- 5. Damaged or chafed wiring between the relay and the ECM giving high resistance
- 6. Blown fuse or a tired fusible link in the relay's supply circuit
- 7. Failing ignition switch upsetting the timing of the de-energise sequence, less common but it does happen
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Scan for all stored codes and check live data. P068A rarely turns up alone, and the codes sitting alongside it usually point you straight at the cause
- 2. Get on the battery first. Check terminals for corrosion and tightness, then load-test it, you want voltage holding above 11.5V under load. A dodgy battery or earth fakes a lot of these
- 3. Pull the PCM power relay out of the fuse box and look hard at the pins and socket for green corrosion, water staining, or heat damage
- 4. Swap the relay with an identical one from a non-critical circuit like the horn or air-con, clear the code, and drive it to see if the fault comes back
- 5. Check the related fuses and fusible links for continuity, ideally under load rather than just a bench buzz test
- 6. If the relay and supply check out, trace the wiring and connectors from the relay through to the ECM for chafing, corrosion, or high resistance at the plugs
Common questions about P068A
Should I keep driving or get it sorted straight away? +
I'd sort it sooner rather than later. The car might run fine for weeks, but the whole nature of this fault is an intermittent power dropout, and that can turn into a no-start when you least want it. If it's still starting and driving normally you're not in immediate danger, but don't ignore it and end up stranded in a car park. A relay is cheap insurance.
Is it the relay itself or the wiring and connections behind it? +
On most cars it's the relay or the battery side rather than the wiring. Worn relay contacts and loose or corroded battery terminals cause far more of these than damaged loom does. The quick way to tell is the relay swap and a battery load test. If both come back clean and the code returns, then you start looking at the connectors and wiring back to the ECM, which is the slower part of the job.
How long does the repair usually take? +
If it turns out to be the relay, you're looking at minutes once you've found which one it is. A battery swap is half an hour. Where it eats time is when the relay and battery are fine and you have to trace a voltage drop or a corroded connector through the loom, that can be an hour or two of diagnostic labour at a garage before any parts go on.
Is a cheap aftermarket relay any good or should I fit OEM? +
For something as basic as a power relay, a decent quality aftermarket part from a known brand is fine and will save you a few quid over the dealer. The thing to avoid is the bottom-of-the-barrel eBay relays, because a weak relay is exactly what causes this code, and fitting a poor one just means you'll be back doing the job again. If the original came from the factory it's lasted this long, so buy a reputable replacement and don't cheap out.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →