2006 Cadillac DTS - Recurring P2A00 Code

Maintenance/Repairs
1

O2 sensor has been changed several times but code P2A00 keeps coming back… from dealership to local mechanics shop. What is going on?.

2

My guess, wire or connector from th O2 sensor to the BCM.
I am not a mechanic, but a shop should have been able to figure that out.
Of course there are other problems that could cause the code.

3

P2A00 CADILLAC code possible causes

  1. Faulty Heated Oxygen Sensor Bank 1 Sensor 1
  2. Heated Oxygen Sensor Bank 1 Sensor 1 harness is open or shorted
  3. Heated Oxygen Sensor Bank 1 Sensor 1 circuit poor electrical connection
  4. Inappropriate fuel pressure
  5. Faulty fuel injectors Intake air leaks may be faulty
  6. Exhaust gas leaks

Read more: https://www.autocodes.com/p2a00_cadillac.html

Changing it (problem #1) without finding the actual cause… could be one of #2 thru #6. Find a better mechanic.

4

My guess, something’s not airtight between the beginning of the engine intake path and the end of the exhaust pipe. All that stuff has to be perfectly air-tight, otherwise the O2 sensor system simply won’t work. On a 2006 one definite possibility is an exhaust system leak. Especially if this car has been used for a lot of short-trip type of driving. That leaves carbonic-acid in the exhaust pipes which will eventually corrode. This sort of leak can be difficult to find, but if diligently pursued by a knowledgeable shop, will eventually turn up.

A shop with a fully functional scan tool can monitor the O2 sensor signals as the engine is run. That’d help eliminate much of the guess-work.

1 Like