So my check engine light came on and I noticed a lack of excelleration and had them give me a reading while I got my oil changed at Midas and also stopped by Auto Zone and had them read it. Auto Zone's reading showed a problem with the O2 sensor and Midas reading showed a problem with the catalytic converter. I took it to my Dodge service center and they diagnosed it as a lack of communication between the O2 sensor and the catalytic converter and said it needed a software update. I told them to do the update and they charged me $92. I got about 30 miles on the car and the problem started again. Has anyone else had this problem? Any ideas of what could be going on?

 

First thing is that unless your out of warranty milage you should not be charged
updates or flashes.Second thought is that the o2 sensor doesn't communicate with
the catalytic conv it reads the airstream passing thru the converter and sends that
dtat to the ECM (engine control module).They probably just reset the CEL code
when in truth they should have replaced the o2 sensor itself.Find another dealer
and ask to have sensor replaced to start with just to eliminate it from the equation.

 

Yep, I've never seen a O2 sensor communicate with a converter. There is an O2 sensor before the converter to monitor the air/fuel ratio and one after the converter to verify that it is working properly. Sounds like sensor 02 is bad.

 

looks like this may have been part of a recall depending on the specific code
check this out. This is part of a service update my friend found.

**Vehicles equipped with a CVT transmission must have the transmission
control module (TCM) checked for the latest software level whenever the
PCM software is updated. If newer TCM software is available, it must be
installed. Failure to maintain software coordination may result in MIL
illumination or driveability concerns.**

 

Again this precautionary paragraph in the Dodge service manuals
relate to ECM programming itself and really should not reflect itself
in the o2 sensor fault.There was a TSB# 18-031-07 for the ECM
reflecting drivability and smoother operation of the CVT which resulted
in more agressive acceleration from a stop and moderate improvement
in mpg.The MIL or CEL indication if it does not reset in 3 driving cycles
(cold to hot x 3)or when reset with a CANBUS OB2II reader is a fault
that should been seen to by a COMPETENT dealer.The o2 sensors
and attached wiring harnesses should be inspected/replaced as part
of the diagnostics.

 

My husband just talked to the service manager at the dealer and they are clearly trying to BS me. They are the only ones getting a P0139 code. The three other readings at other places have been P0420 which indicates a problem with the catalytic converter.
the service manager claims they have to start with the cheapest fix first which was the flash. Of course they diddnt explain that before. Im going back tomorrow. I'm curious to see what happens.

 

This is what it says in the service manual with regards to P0420:



P0420-CATALYST 1/1 EFFICIENCY
For a complete wiring diagram Refer to Section 8W.
² When Monitored:
After engine warm up, at medium throttle with vehicle speed between 35 and 60 mph.
² Set Condition:
If the switch rate of the downstream O2 sensor is within the calibrated fail threshold during monitoring. Two trip
fault. Three good trips to turn off the MIL.

Possible Causes
EXHAUST LEAK
ENGINE MECHANICAL CONDITION
AGING O2 SENSOR
CATALYTIC CONVERTER

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -DIAGNOSIS AND TESTING).

Diagnostic Test
1. EXHAUST LEAK
NOTE: A thorough exhaust leak test must be completed before removing an O2 Sensor or any other part
from the exhaust system. Do not remove any parts before an exhaust leak check has been completed.
NOTE: An exhaust leak may cause downstream fuel adaptives to rail out, resulting in a false O2 Sensor
failure
Turn the ignition off.
Inspect the exhaust system for leaks between the engine and the 1/1 Oxygen Sensor.
Inspect the exhaust system for leaks between the engine and within 6 inches downstream of the 1/2 Oxygen Sensor.
Perform a leak test with Miller Tool #8404A Evaporative Emissions Leak Detector (EELD), even if an audible leak is
not heard. Pay particular attention to the exhaust manifold to head surface, exhaust pipe to manifold connection,
and the O2 sensor boss for leaks.
Connect the SMOKE supply tip (black hose) to the exhaust cone adapter (if equipped) and place it into the tail pipe.
Set the smoke/air control switch to SMOKE.
Press the remote smoke/air start button.
While still holding the remote smoke/air start button, use the white light (#8404-CLL) to follow the exhaust system
path and look for a leak, indicated by exiting smoke.
If a leak is concealed from view, release the remote smoke/air start button, and use the ultraviolet (UV) black light
#8404-UVL and the yellow goggles 8404-20 to look for residual traces of dye that is left behind by the smoke.
The exiting smoke deposits a residual fluid that is either bright green or bright yellow in color when viewed with a
UV light.

Were any exhaust leaks found?
Yes >> Repair as necessary.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No >> Go to 2

 

Bigtsr, you are a great source of knowledge. Your help here is greatly appreciated!!

 

looks like they finally got the P0420 reading and now want to replace the catalytic converter. The people at my Dodge service department are a fry short of a happy meal so it's been quite a pain in the neck but I think Im starting to get somewhere with them. Thanks for all of your help. I'll let you know what happens.

 

Good luck. Might be time to try another dealer as well!!