Q: Q: limp mode

asked by on

hello . i have a 2008 GMC 2500 HD . it goes into limp mode off and on . 1st time it did i was on the highway and it down shifted into 2nd gear .locked up the rear end and revved up so i put it in neutral . the door locks went crazy going up and down .. lost speedo , lost trans temp gauge . lost tow haul , the brake pedal makes a clicking sound when you depress it . i have a friend with OBD2 and it said lost communication with TCM . i then cleaned All fuses , fuse box , and connectors , added a ground wire to engine . cleaned all ground wires i could find . replaced the alternator .. i am lost now what to do because it still goes in and out of limp mode ?

My car has 50000 miles.
My car has an automatic transmission.

This problem may be a wire connection or TCM or PCM issue. The first thing that has to be done is to get communication with the TCM. The different computers communicate all to the engine computer and then to the data link. If one or more modules do not communicate then the engine goes into limp mode. I can only recommend having a mechanic like one from YourMechanic to go through complete diagnosis for the no communication error you have to isolate the cause of the problem on this one since the wiring is a major factor on these vehicles along with TCM.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Q: limp mode

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: Steering wheel hard to turn; car squeaky

Hello, I have recently encountered this steering problem in a Chevy Avalanche, which is very similar vehicle to your GMC Yukon. Rest assured that all the symptoms your car is experiencing are likely connected to one thing, the power steering....

Q: I have checked the oil level and the oil level on the dipstick is far over 'maximum'. Should I carry out a full service?

You should find out the reason the oil is overfull. If the oil is contaminated with water then you may have a head gasket blown. If the oil is contaminated with fuel then you may have a fuel injection system...

Q: Bad idling after coolant temp sensor replacement

If you have a bad knock sensor, then the engine timing may be going too low and causing the low rough idle. If the scanner gives a code, then have it diagnosed and fixed. A vacuum leak will also cause...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.