Skip the auto shop - Our mechanics make house calls

Q: Car suddenly went into limp mode

asked by on

After some off-roading last friday, the car suddenly went into in limp mode, doesn't go faster than 40Km/h with the pedal to the metal and makes awful sounds. I don't know if it's related but have recently changed brake pads and brake sensor switch, transmission oil

My car has 157000 miles.
My car has an automatic transmission.

A: Hello and thank you for contacting Your Mec...

Hello and thank you for contacting Your Mechanic. Your Hummer could have the brake system engaged for the traction control. Disable the traction control and see if the engine will increase in speed.

Another thing to check is the parking brake cable. See if the cable is snagged on anything causing the vehicle to have a dragging resistance in the brakes. If the brakes are free and working correctly and if the engine continues to be in limp mode, then there could be an issue with the transmission.

Check all of the harness connections to all of the sensors on the transmission and transfer case. If all of the connections are tight, then I recommend having a professional, such as one from YourMechanic, drive your Hummer and determine why your car isn't getting enough power and is making unusual noises.

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・Save up to 30%

Get a quote

What others are asking

Q: Knocking sound

Hello. It sounds like there is something broken in the engine internally. A push rod could be bent, a lifter could be stuck, or the engine bearing could be messed up. Have your vehicle's noise inspected by a certified technician,...

Q: DSG transmission or exhaust issue?

answering

Q: Oil Pressure Issues

The PCV system on this engine is incorporated into the air filter housing and has no serviceable parts. If there is excessive oil in the air filter housing then the entire housing would need to be replaced as an assembly....

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
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.