Skip the auto shop - Our mechanics make house calls

Q: Shifts early jerks engine - 1994 GMC K2500

asked by on

My truck has 235,500 miles on it. The 4x4 wasn’t working, so I replaced the actuator and that helped. I replaced the pins and bushings in the doors and fixed the window track. But I am getting a Diagnostic Trouble Codes 28 and 32. The 32 code is for an Exhaust Gas Recirculation problem. The 28 is for a quad driver module that I don’t know anything about it. My truck shifts early sometimes jerking the engine, and it will only shift into drive periodically. Some people tell me to replace the computer and some say to replace parts in the transmission. My plug is good in the transmission with No leaks. I used a SOLUS scan tool to check the codes, so I am very sure of my problems. Can you help me figure this out, and give me some ideas on how to fix this?

Hello. You will need to remove the EGR valve to clean out the carbon and then decarbonize the engine. The code 28 may be due to the transmission or transmission module controller PCM has a bad internal driver to control the transmission shifting is in failure mode. Have the engine and transmission grounds checked to the see if they are loose or corroded. If you would like to have this looked at, a certified technician from YourMechanic can come to the site of the car to diagnose the shifting issue and let you know what needs to be repaired.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: My 99gmc suburban backfires in the throttle body, won't start.

If you were getting a rattling noise in the lower front of the motor then you engine may have jumped timing. The timing chain may have been so worn that it jumped ignition timing between the crankshaft and camshaft. That...

Q: The left wheel on the rear end lock up

Hello there. This is not uncommon on the Chevy K2500. There are a few possible causes for the wheel to get locked. The most likely would be low differential fluid, differential side gears, a ring and pinion failure, or a...

Q: What does it mean when the interior alarm sounds continuously?

The interior alarm can sound in a variety of ways to alert you when something is not correct. The alarm will sound continuously if you attempt to open a door and exit the vehicle when the shift lever is in...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...