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!
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!