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Dan, Technician
Category: Cadillac
Satisfied Customers: 24419
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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2002 deville: engin..keeps coming on after resetting.

Resolved Question:

My 2002 deville service engin soon lt. keeps coming on after resetting. Error code indicates cat. converter below level, but this was changed, and the O/2 sensors as well.
Submitted: 6 years ago.
Category: Cadillac
Expert:  Dan replied 6 years ago.

Welcome to JustAnswer, my name is XXXXX XXXXX I'm here to help get your problem resolved. Ask follow up questions, thanks.


What is the actual codes your getting? Was converter replaced with OEM replacement or aftermarket?

Customer: replied 6 years ago.
catalist below level. No it was replaced with an aftermarket one.
Expert:  Dan replied 6 years ago.

Sometimes these vehicles can be picky with aftermarket converters.......I've used magnaflow and have had good luck otherwise you can get a OEM from


Possible CausesSetting Conditions
  • Base engine problems (e.g., high engine oil or high coolant usage)
  • Catalytic converter has failed (check for physical damage and discoloration)
  • Check for air leaks in the Air Induction system (e.g., in the intake manifold)
  • Check for air leaks in the exhaust manifold and in the exhaust pipes
  • Continuous engine misfire conditions, or weak or low coil output
  • Front HO2S or rear HO2S is contaminated with fuel or moisture
  • Rear HO2S is loose in the mounting hole (check it for a leak)
DTC P0030, P0036, P0101, P0102, P0103, P0106-P0108, P0112, P0113, P0116-P0118, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0150, P0151, P0152, P0153, P0154, P0155, P0171, P0172, P0174, P0175, P0201-P0208, P0300, P0335, P0336, P0340, P0341, P0351-P0358, P0385, P0386, P0404, P0405, P0410, P0412, P0418, P0440, P0442, P0443, P0446, P0449, P0452, P0453, P0502, P0503, P0506, P0507, P1031, P1032, P1133, P1134, P1336, P1359, P1360, P1372, P1415-P1416, P1441, P1153 and P1154 not set; engine runtime over 10 minutes; engine speed more than 800 rpm for 46 seconds since end of last idle period, engine running at idle speed (± 100 rpm of Desired Idle) for 60 seconds in Closed Loop, system voltage over 10.7v, BARO signal over 75 kPa, ECT signal from 160-248ºF, IAT signal from 21-329ºF, Predicted Catalyst Temperature from 788-1,202ºF, number of tests this ignition cycle less than 6, and the PCM determines that the catalytic converter efficiency was too low. The PCM tests the ability of the catalytic converter to lower exhaust emissions. The PCM determines the performance of the catalytic converter by calculating the oxygen storage capacity. The PCM calculates this data by comparing the oxygen content of the exhaust entering the catalyst, read from the front and rear heated oxygen sensor (HO2S) to that leaving the catalyst, read from the post HO2S.

This code sets in 1 Trip(s).
This code will turn on the MIL (Malfunction Indicator Lamp)

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