Causes of P0968 engine code
From what I see most often in the shop, there are a handful of usual suspects behind a P0968 code. Here’s what tends to cause it:
- Faulty pressure control solenoid "C" - this is the part itself failing
- Dirty or contaminated transmission fluid - old or burnt fluid can gum things up
- Clogged or restricted transmission filter - this can choke off fluid flow
- Bad transmission pump - if it’s not making enough pressure, the solenoid can’t do its job
- Defective valve body - the part of the transmission that directs fluid where it needs to go
- Blocked hydraulic passages inside the transmission
- Corroded or damaged connectors
- Broken or damaged wiring going to the solenoid or PCM
- Faulty PCM (the car’s main computer) - rare, but it happens
In my experience, dirty fluid or a bad solenoid are the most common, but wiring and connector issues are right up there too, especially on older vehicles or those exposed to harsh conditions.
Symptoms of obd code P0968
If your car has a P0968 code, you’ll probably notice a few things right away. Here’s what drivers usually tell me:
- The check engine light is on
- Shifting feels rough or harsh - sometimes it really bangs into gear
- The transmission might slip, meaning the engine revs but the car doesn’t accelerate like it should
- Poor fuel economy - you might notice you’re filling up more often
- Transmission overheating - sometimes you’ll even get a warning light for this
- In some cases, the car goes into a sort of "limp mode" where it won’t shift out of a single gear
Honestly, if you’re feeling any of these, especially harsh shifting or slipping, it’s best not to keep driving. Things can go south quickly if overlooked.
Diagnosis of P0968 code
Here’s how I usually approach a P0968 code, step by step:
- First, I always check for Technical Service Bulletins (TSBs) for your specific car. Sometimes there’s a known issue and a quick fix.
- Next, I check the transmission fluid level and condition. Low, dirty, or burnt fluid is a red flag. If it’s dark or smells burnt, that’s a problem.
- Then, I look at the service history - when was the last time the fluid and filter were changed? If it’s overdue, that’s a likely culprit.
- After that, I do a thorough visual inspection of the wiring and connectors going to the transmission, solenoids, and PCM. I’m looking for broken wires, corrosion, loose plugs, or anything out of the ordinary. Don’t forget to check connectors for greenish corrosion - that’s a surefire way to end up in trouble.
- If everything looks good so far, I’ll use a digital multimeter to check for continuity in the wiring to the solenoid. You want to see 0 ohms - any resistance or an open circuit means there’s a break somewhere.
- If the wiring checks out, I’ll move on to testing the solenoid itself. Sometimes you need to remove the transmission pan to get to it. I’ll check its resistance and see if it’s within spec for your vehicle.
- If all else fails, I’ll check the transmission pump and valve body for issues, but that’s getting into more advanced territory.
It’s better to have someone assist you with the basics, especially when checking fluid or getting under the car. And always disconnect the battery before poking around electrical connectors.
Common Mistakes when fixing P0968 trouble code
I’ve seen a few common mistakes when folks or even some techs try to tackle this code:
- Jumping straight to replacing the solenoid without checking the fluid or wiring first - that can waste time and money
- Overlooking corroded connectors - a little green corrosion can cause big headaches
- Not checking for TSBs - sometimes there’s a known fix that gets missed
- Confusing this code with engine misfire or unrelated transmission issues
- Skipping the basics, like checking fluid level and condition, before diving into expensive repairs
My advice: always start simple and work your way up. It’s easy to miss something obvious if you rush.
Seriousness of dtc P0968 issue
This isn’t a code you want to put off. While it might start as a moderate issue, it can quickly turn serious. If the transmission keeps banging into gear or slipping, you risk permanent internal damage - and that can mean a full rebuild or replacement. Parts like the clutches, bands, and even the valve body can get ruined if you keep driving with this problem. Honestly, it’s dangerous to ignore this, especially if you notice harsh shifting or the transmission overheating. The risks just aren’t worth it.
How to repair P0968
Here’s what I usually see as the most effective repairs for a P0968 code:
- Change the transmission fluid and filter if they’re dirty or overdue
- Replace the faulty pressure control solenoid "C" if it’s out of spec
- Repair or replace any damaged wiring or connectors
- Clean corrosion from connectors and make sure everything’s tight
- Flush the transmission to clear out any blockages in the hydraulic passages
- Repair or replace the transmission pump or valve body if they’re found to be faulty
- In rare cases, reprogram or replace the PCM if it’s the root cause
In cases like this, it’s usually best to start with the simple stuff - fluid, filter, wiring - before moving on to the more expensive repairs.
Conclusion
To sum it up, P0968 means your transmission isn’t getting the right signal to control fluid pressure, usually because of a problem with solenoid "C" or its wiring. It’s a moderate-to-serious issue that can quickly get worse if ignored, risking major transmission damage. I recommend starting with a fluid and wiring check, then moving on to the solenoid if needed. Don’t put this off - the most reliable fix is to work through the basics step by step, and you’ll avoid much bigger headaches down the road.
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