Q: P0420 motor mounts on a Hummer H3?

asked by on October 04, 2017

I have a 2008 Hummer H3 that is throwing P0420. I decided to take it to a dealer because I also needed the a/c recall work done. THey diagnoses the problem as motor mounts and quoted a high price for repair. Is that a possibility or was I lied to? I don’t want to chase something if that’s what it is. But I fail to see how motor mounts could mimic an O2 sensor or cat converter.

My car has 136000 miles.
My car has an automatic transmission.

Hi Jimmy. Thanks for contacting us today. I’m in agreement with you - in that the replacement of engine mounts is NOT a solution to resolve a P-0420 Error Code. You should read this article about this code - to review possible causes and repair options. What is likely is that Hummer dealer completed a (100-point inspection) along with the scan and determined that the motor mounts were damaged and required replacement. It’s also possible that they never resolved the error code. I’d ask them to explain how motor mounts are related to this code - as we’d be curious to see this explanation as well.

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

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

Car dies after charging battery

The symptoms described for your Mitsubishi Outlander lead me to believe you are dealing with a weak battery. As batteries age, they lose the ability to hold a charge. The Check Engine Light could be on as a result of...

Car shudders in gas pedal and steering wheel, higher than 60 mph

If you did not have any issue before the tires were put on and now the problem has appeared, than this indicates that there is tire problems. I would recommend having the tire store put a different brand of tires...

Changed alternator and battery, but still says check charging system

Hello and thank you for writing in! This is likely a sign of a bad voltage regulator. This is a unit that regulates the charging of the battery from the alternator. When this is not functioning properly, this can cause...

Related articles

Understanding the Hummer Oil Life Monitor Service Indicator Lights
Car symbols, or dashboard lights, are a car service reminder. The Hummer Oil Life Monitor (OLM) system indicates when and what service your car needs.
How to Get Hummer Dealership Certified
Hummer car dealerships offer automotive technician jobs to mechanics who are Hummer certified through the Universal Technical Institute.
Hummer Certified Pre-Owned (CPO) Car Program
If If you are in the market for a used Hummer vehicle, you may want to check out cars under their certified pre-owned program. Many manufacturers have a certified pre-owned (CPO) program, and each one is set up differently. Read...