You pull into your driveway after a normal commute, turn the key off, and go inside. The next morning, you start the car, and the engine runs perfectly fine—but a bright yellow Check Engine Light is staring you right in the face.
You plug in your code reader, and it spits out Code P068A.
Most drivers immediately assume the worst when they see the letters "ECM" (Engine Control Module). Dealerships might even try to convince you that the main computer is failing. Stop and take a breath. Your engine computer is likely perfectly healthy. It is just complaining that someone "pulled the plug" on it too fast last night. Let's explain what this code actually means and how to fix it for under $15.
What Does Code P068A Mean?
The technical definition is "ECM/PCM Power Relay De-Energized Performance - Too Early."
Think of your car's engine computer (PCM) like a desktop computer. When you want to turn off a desktop computer, you don't just yank the power cord out of the wall. You click "Shut Down," and the computer takes a few seconds to save files, close programs, and safely turn itself off.
Your car's PCM does the exact same thing. When you turn the ignition key to OFF, the engine stops, but the PCM needs to stay awake for a few more seconds to save the current fuel trims, record transmission data, and reset the electronic throttle body. It gets this temporary power through the PCM Power Relay.
When you get Code P068A, the computer is saying: "When the driver turned the car off, the Power Relay cut my electricity instantly. I didn't get a chance to save my data!"
Most of the time, the only symptom is the Check Engine Light. However, because the computer couldn't save its idle data, you might experience a slightly rough idle or a minor hesitation the next time you start the car, as the computer has to relearn the idle parameters from scratch.
Top Causes: Who Pulled the Plug?
If the computer lost power too early, there is a physical disruption in the electrical supply line:
- A Failing PCM Power Relay (Most Common): Relays are simple mechanical switches that click open and closed inside your fuse box. Over time, the internal contacts get worn out or sticky. When you turn the key off, a worn relay might snap shut instantly instead of holding a delayed connection.
- Loose Battery Terminals: If your battery clamps are even slightly loose, the vibration of the engine shutting down can cause a micro-second power interruption. This tiny drop in voltage is enough to trigger the code.
- Weak or Dying Battery: A battery that drops below 9.6 volts during the shutdown or startup sequence can cause the relay to drop out prematurely.
- Corrosion in the Fuse Box: Water intrusion or road salt can corrode the pins underneath the power relay, creating high electrical resistance.
Stop Guessing: Check the Module Voltage
Is your relay dead, or is your battery failing? Don't blindly replace parts without checking the data.
Using a professional diagnostic scanner like the iCarsoft CR Pro S, you can dive into the Engine Control Module's Live Data and look at the "Ignition Voltage" or "Module Supply Voltage." You can monitor this exact voltage while turning the key off to see if the power drops abruptly. Furthermore, the scanner can test your battery's resting health to rule out a failing alternator or weak battery cells.
Check Module Voltage with iCarsoftHow to Diagnose and Fix P068A
Step 1: Tighten the Battery Cables
Pop the hood and grab your battery terminals with your bare hands. Try to twist them. If you can move the terminal even a millimeter, it is too loose. Grab a 10mm wrench, tighten both the positive and negative terminals until they are rock solid, clear the code, and see if it returns.
Step 2: The "Relay Swap Test" (The Best DIY Trick)
Open your under-hood fuse box and look at the diagram on the lid. Locate the "PCM Power" or "ECM Relay." Now, find another non-essential relay in the box that has the exact same part number and size (the Horn relay or AC Compressor relay are perfect choices).
Swap the PCM relay with the Horn relay. Clear the codes. Drive the car for a day. If the P068A code never comes back (but your horn stops working), you just proved the relay was bad! Go buy a new $15 relay.
Step 3: Inspect for Corrosion
If you pull the relay out and notice the metal legs are coated in green fuzz (copper oxide), you have a moisture problem. Spray the fuse box terminals with an Electronic Contact Cleaner and gently scrub them with a small wire brush.
Frequently Asked Questions (FAQ)
Yes, it is generally safe. Because this code relates to the shutdown sequence, it rarely affects the vehicle's driving performance. However, you may experience a slightly rough idle right after starting the car, as the computer forgets its learned idle settings.
Usually no. P068A means the relay shut off too early. However, if the relay is physically failing, it could eventually get stuck in the "ON" position (which triggers a different code, P068B). If it gets stuck ON, it will absolutely drain your battery overnight.
If you perform the "Relay Swap Test" and determine the relay is bad, the part will cost you between $10 and $25 at any auto parts store. If you take it to a dealership, expect to pay between $100 and $150 for a diagnostic fee plus the cost of the relay.
