This Pacifica sets multiple O2 codes. Originally it set a upstream O2 code and later set catalyst efficiency code. I replaced both sensors to make sure they were both good even though they seemed to be switching ok on the scanner. Now it came back with a P2097, downsteam fuel rich 1/2. I gave the O2 readings below and the fuel trim numbers. Any suggestion? Could it have a bad converter?

Thanks.

Related Repair History
I replaced the upstream and downstream o2 sensors. It had previously set upstream o2 code and catalyst efficiency code P0420.

Randy Hiebner
Technician
Tri County Automotive
Henderson, Nebraska, USA
FIX posted on Jan 25, 2010 4:38:02 PM
Thanks too all who responded. I had installed Bosch O2 sensors. I for know have replaced the downstream sensor with an OE Chrysler sensor and the problem hasn't reoccured.

Thanks again, Randy.
Manifold Vacuum Readings

Idle: 18.9 in.


Computer Codes & Descriptions

P2097- Downstream fuel system rich 1/2


Other Test Results

Upstream V. - 2.5-3.4 v
Upstream Desired V. - 2.06 v
Downstream V. - 3.11 v
Short adapt - -3% to 2%
Long term at idle - 12.5%
Long term at 2000 RPM - 9.8%

5 Replies Received (Hide Replies)Please only use this feature to report severe guidelines violations.

Reply 1 Clifford from Texas Jan 20, 2010 10:47:30 AMin the absence of an exhaust leak this code is almost always an aftermarket (usually bosch) o2 sensor. check the integrity of the entire o2 circuit and if good shoot the o2 sensor.

p.s. chrysler converters are failing at an astounding rate. when you replace the o2 prepare for a return of the p0420

Reply 2 from New Mexico Jan 20, 2010 11:19:16 AM check temp inlet and outlet on cat. should be 10% hotter on outlet


Reply 3 Matthew from Illinois Jan 20, 2010 11:37:47 AMIt is not the converter. This is a downstream sensor monitor failure. 2 things to check: 1. make sure there are NO misfires: reason extra reactants in the exhaust will cause a higher downstream voltage 2. Check the downstream heater operation (make sure the chassis ground wire for the heater has nearly zero volts on it) reason: PCM supplied bias will "bleed" over into the signal sense when the sensor cools off (making the internal resistance higher)


Reply 4 Gilbert from Massachusetts Jan 21, 2010 5:01:13 AMThis code can set if a new cat has been put on. If this is the case, the monitor should pass after the new cat gets about 500 miles on it. The other reason it would fail is the use of aftermarket O2 sensors. Mopars need factory O2s to work properly. Also, after replacing O2s on Mopars you need to do a battery disconnect to force the PCM to learn O2 heater resistance values. Failure to do this step will result in improper O2 heater operation.


Reply 5 Charles from Massachusetts Jan 21, 2010 6:43:41 AM also make sure they are plugged into the proper connectors

this info borrowed from Iatn.net