2012 Sonic - flashing "D" light

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Jul 7, 2014
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Location
Winnipeg MB CA
Hello wise Bitoggeratti - My friend phoned earlier today, a bit panicked. His Sonic (1.8 l, automatic) was running very poorly, the check-engine light was on (solid, not flashing), and the "D" light on the transmission gear selector was flashing. He limped over with the car (worried the car wouldn't make it), with the tranny taking a long time to engage.

He parked a few houses away due to construction on our street. We went out, and I started the car. It ran perfectly, and the "D" light did not flash when I put the car was in gear. The check-engine light was still on. Drove the short distance to my house and pulled the car into my driveway. My friend said that this had all started after he'd unintentionally shifted from R to D at low speed without stopping in between.

I read the code - P0601 (PCM internal fault) - and cleared it. It did not come back. My ScanGauge had detected two codes, but unfortunately I cleared both before I'd read the 2nd one.

At this point, I figured the car had just needed a "reboot" and had fixed itself just sitting a few minutes while my friend walked from the car to my house and we walked back. Regardless, I disconnected the negative battery terminal for a minute or so. Again, no problem once he restarted it.

So, what happened here? Did the inadvertent shift from R to D confuse the computer and send the car into limp mode? Or is that coincidental, and there's an underlying problem with the transmission that will resurface?

The car is a bit short of 120K km (75K miles) and I don't think the tranny has been serviced yet. There's no dipstick, so I'm leery of taking this on myself - I recommended that my friend have the fluid changed (not flushed) at a reputable transmission shop. I don't know if these have a filter that should be changed, or just a strainer that can be left alone.

Thanks all!
 
Shifting from R to D (or vice versa) is never good on any auto transmission.

Considering this silly stunt does not seem to affect the car after clearing the codes, I wouldn't be worried.
 
Lolvoguy said:
Shifting from R to D (or vice versa) is never good on any auto transmission.

Considering this silly stunt does not seem to affect the car after clearing the codes, I wouldn't be worried.
 
Last edited:
Originally Posted by ffhdriver
I don't understand your comment. How do you shift from R to D then?
I am pretty OCD about it when driving an automatic - I come to a complete stop in R before shifting to D. I never shift to D while the car is still moving backwards.
 
I think the Sonic is the same as my Trax. Drop belly pan, drain plug is 10 or 11mm. Takes 4 1/4 qts if I remember right. Fill plug is easy to get to, need a long funnel. 45 minute job tops. There are youtube videos on the internet. Mine takes Dex6.
 
Originally Posted by ffhdriver
I don't understand your comment. How do you shift from R to D then?

You come to a complete stop prior to selecting any other gears.
 
Originally Posted by c502cid
I think the Sonic is the same as my Trax. Drop belly pan, drain plug is 10 or 11 mm. Takes 4 1/4 qts if I remember right. Fill plug is easy to get to, need a long funnel. 45 minute job tops. There are youtube videos on the internet. Mine takes Dex6.

We have a 2015 Sonic 1.8l automatic .

There is a drain plug on the bottom of the tranny , a " check " plug on the side and a fill plug on the top .

Drain the tranny , then replace the plug . You may wish to measure the amount of Dexron 6 that comes out .

With the car level , remove the side " check " plug and fill until ATF comes out . Put everything back together and do a long enough test drive , to get the ATF warm / hot .

Back home , jack it back up and run it through the gears , with the brake FIRMLY applied and return to Park . Remove the check plug ( with the car level ) and add enough ATF for it to come dribbling out the check hole . Put everything back together & you are finished .

Next thing is , has the timing belt & related parts , been replaced ? The coolant pump is driven by the serpentine belt , I think . I would not mess with it , if it is not giving any problems .
 
Is the factory battery still in it? I'm wondering if it's borderline maintaining ~14VDC at idle.

Hard to say what this could have been, or if the other code would have helped.

Just a wait and see if it comes back.
 
My wife had an HHR that she valet parked.

The valet must have gone from R to D, as it threw a code complaining about it. It did NOT light the CEL and the only symptom was the cruise control stopped working.

Cleared the code and all was well.

A PCM internal fault could be many tragic things, like bad caps, solder joints.
 
Originally Posted by c502cid
I think the Sonic is the same as my Trax. Drop belly pan, drain plug is 10 or 11mm. Takes 4 1/4 qts if I remember right. Fill plug is easy to get to, need a long funnel. 45 minute job tops. There are youtube videos on the internet. Mine takes Dex6.

Originally Posted by WyrTwister
Originally Posted by c502cid
I think the Sonic is the same as my Trax. Drop belly pan, drain plug is 10 or 11 mm. Takes 4 1/4 qts if I remember right. Fill plug is easy to get to, need a long funnel. 45 minute job tops. There are youtube videos on the internet. Mine takes Dex6.

We have a 2015 Sonic 1.8l automatic .

There is a drain plug on the bottom of the tranny , a " check " plug on the side and a fill plug on the top .

Drain the tranny , then replace the plug . You may wish to measure the amount of Dexron 6 that comes out .

With the car level , remove the side " check " plug and fill until ATF comes out . Put everything back together and do a long enough test drive , to get the ATF warm / hot .

Back home , jack it back up and run it through the gears , with the brake FIRMLY applied and return to Park . Remove the check plug ( with the car level ) and add enough ATF for it to come dribbling out the check hole . Put everything back together & you are finished .

Next thing is , has the timing belt & related parts , been replaced ? The coolant pump is driven by the serpentine belt , I think . I would not mess with it , if it is not giving any problems .
c502cid & WyrTwister - Good thoughts! If this were my car, I'd certainly take it on. Given that it's my friend's car, I'm reluctant to change fluid for him, and then risk bearing responsibility if the transmission fails at some point down the road.

I did a tune-up for a former friend many years ago (on a Plymouth Fury III w/ 383) and the timing chain failed a few days later. He blamed me for it, and bullied me into giving him some tires to compensate him. That was a lot of years ago, but I've never quite gotten over it. In retrospect he was pretty toxic (though very charismatic), and I was better off not having him in my life. In any case, I'm reluctant to put myself in a position where I might be blamed for an unrelated failure.

This is the same car I wrote about a few weeks ago, where a routine inspection by a garage doing a seasonal tire changeover had pointed out sloppy stabilizer-bar end links, a weeping strut, and a blown rear shock. I noticed at the time that the engine had a timing belt rather than a chain, and asked my friend the mileage. I thought he said 150K km. We checked the manual, and it recommended the belt be changed at 156K km, so I told him he shouldn't let it go.

But we checked the odometer during this recent transmission issue, and it's only at 117K km, so he's got lots of mileage left on the old one. I must have misheard (perhaps he'd said 115 rather than 150) a few weeks ago, or perhaps he was mistaken. In any case, I'm not sure whether I'd take on his timing belt or not. I've done several for myself, and a few for others, but it's always a risk.
 
The car is still misbehaving. The car is on loan to my friend's daughter and family, and they've taken it to a trusted local garage. The mechanic has checked for external problems (bad grounds, weak battery, etc.) and figures the problem is internal to the transmission. Although the fluid is original, the mechanic says it looks pink and unburnt.

Automatics are black boxes to me. I keep the fluid fresh, and hope for the best. If it were my car, I would have been doing a drain-and-fill with synthetic ATF every couple of years.

The fact that the car is OK for days at a time after the problem occurs and goes away indicates to me that the problem is likely not due to a mechanical problem (i. e. bad TC or clutches), but as I said, I know almost nothing about automatics.

Anyway, I've advised my friend to take the car to a local transmission specialist I've recommended.

Is anyone here on BITOG familiar with the Sonic's AT? Any thoughts on what this would likely be?

Thanks in advance!
 
I would send a pm to clinebarger on here about the issue and see if he could respond on the thread so we could all read it.
 
Update ... My friend dropped the car off at a well-regarded transmission shop earlier this week, and of course the car was working perfectly. The tech drove it several times over the next few days until it finally exhibited the symptoms again. Per my friend, the shop's diagnosis was a bad PCM (although since they said it's in the valve body, perhaps they said TCM). It's an expensive part, but much cheaper than a used transmission.
 
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