Chevy Suburban ABS, Heater, Code P0420

Problem with my 1996 Chevrolet Suburban. 5.7 V8.
Question = after the engine is started on my 1996 chevy Suburban Tahoe the ABS lights won't go out and no other electronics work, eg- no heater, no electric windows, no wipers etc.... What would cause all of these problems at the same time? Some times if truck is driven over a sharp bump, the antilock light goes out and everything works as per normal. Thanks very much for your time and help ith this issue.

Answer:
Sounds like an electrical problem is related to all these things. Most likely a ground. First check that the battery cables are clean and tight. Next, I would suggest having one person in the truck, and another under the hood pulling on wiring harnesses. The person in the truck would see some change in the systems that are acting up if a loose connection or a ground wiring problem was moved by the other person. This sounds like a ground problem. There are many grounds under the hood, under the truck, and the dash. Looking over several schematics would be needed to determine if there is a ground in common with all these systems. A common area is on the back side of the intake manifold right against the firewall. Two or three ground wires attach there on a bolt and it comes loose.

chevy suburban

Question:
1998 Chevrolet Suburban problem.I have replace the Catalytic converter 2 times and o2 senors 1 time and the spire fuel management system for injectors. I keep getting the code P0420 on my vehicle i do not know what to do now.

Answer:
Is the exhaust in the truck the system with 2 catalytic Converters just after each manifold, (y- pipe setup) or are there 2 converters, one further down the exhaust then the other?

Visitor reply:Yes there are 2 converters. One for each bank and they meet at the muffler.

Answer:
OK, thanks. Check engine light code P0420 is very straight forward of bad #1 cat. 2 possibilities. Either the replacement converters are of poor quality and not cleaning the exhaust up enough for the computers readings, or something is burning them up. A constant misfire will burn up a converter, an inaccurate o2 sensor can also make for a rich condition and cause a converter to go bad after a period of time.

Poor quality fuel, or high alcohol level can damage a cat., as well as engine burning coolant or oil. Need to have a detailed overall diagnosis of the engine and control systems. I will run this past the other guys and see if they have any other ideas.

Question:
2003 CHevy SUBURBAN 5.3 Vortec, SPEEDO NOT WORKING. AT FIRST THE SPEEDO WAS NOT REGISTERING THE RIGHT SPEED NOW THE NEEDLE DOESN'T MOVE AT ALL.

Answer:
More than likely you have a faulty instrument cluster. I've seen this many, many times on the 2002 to 2006 GM truck line. Usually the speedometer will start to act funny or the needle will stay at a certain MPH when the truck is stopped, or it will not function at all. The internal problem in the IPC is the motors that drive the gauge. You will need to replace the instrument cluster assembly or send it out for repairs or an exchange remanufactered unit. The only thing that is really involved, is that you will need to have the cluster programmed at a GM dealership. Otherwise, the gauges will not work correctly and the miles won't be right on the display. They can do the entire job if you so desire. Expect to pay about 1 hour labor just for a programming service.

Question:
Chevrolet 2002 Suburban 1500. Tow / haul light turns on and off by itself. Question = The tow/haul light turns on and off by itself and need some information on this probem.

Answer:
You've either got a bad switch in the shifter handle, or the wiring that runs from the switch and down the steering column has become rubbed through or broken and is shorting out. I've seen both instances on your type of vehicle. If you can remove the trim panels around the steering column, you can inspect the wiring for the switch. It is two very small gauge white wires that control the switch function. If the wiring looks good, you'll have to replace the shifter handle which would include a new tow/haul switch assembly.


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