EVAP and cat sensors

Tiny
EAGLE01
  • MEMBER
  • 2003 CADILLAC DTS
  • V8
  • AUTOMATIC
  • 80,000 MILES
2003 cadillac DTS
had cat replaced, 3weeks later code 420 came up, cleared code, came back after 2 weeks, mechanic was going to replace oxygen sensors but didn't get to it and inspection came due so he wiped codes. Now all sensors came back up except cat and evap. Have been trying to get these sensors up for 2 weeks and neither will come up. There are no codes showing.
What can be done?
Do you
have the same problem?
Yes
No
Saturday, June 11th, 2011 AT 2:02 PM

1 Reply

Tiny
WRENCHTECH
  • EXPERT
You should never clear a computer to get an inspection. As you can see it can take forever for all the monitors to reset. It's looking for a specific set of circumstances.

INSPECTION/MAINTENANCE (I/M) CATALYST SYSTEM SET PROCEDURE

DESCRIPTION
The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the catalyst system. The test may be used to set the I/M System Status indicators to YES. The I/M System Status display on the scan tool provides an indication of whether the control module has completed the required tests. The I/M System Status does not indicate that the tests have passed or failed. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the other tests for that system have not run.

CONDITIONS FOR RUNNING

* The barometric pressure (BARO) is more than 75 kPa.
* The engine coolant is at operating temperature, 95-100 C (203-212 F).
* The intake air temperature (IAT) is between -6 to +200 C (21-392 F).
* The engine is in Closed Loop fuel control.
* The engine has run for 10 minutes off idle in order to initiate test.
* The battery voltage is between 10-16 volts.

DIAGNOSTIC AIDS
The control module runs a maximum of 12 tests per trip until the Catalyst System Status updates to YES. If the status does not update, the test outlined in this procedure can be repeated until the I/M System Status updates to YES.

If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load such as a cooling fan or A/C compressor clutch turning ON may cause the test to abort.

INSPECTION/MAINTENANCE (I/M) HEATED OXYGEN SENSOR (HO2S) HEATER SYSTEM SET PROCEDURE

DESCRIPTION
The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the heated oxygen sensor (HO2S) system. The test may be used to set the I/M System Status to YES. The I/M System Status display on the scan tool provides an indication of whether the control module has completed the required tests. The I/M System Status does not indicate that the tests have passed or failed. When all of the diagnostics for a specific system have run and passed, the I/M System Status will update to YES. If a test for a specific system has failed, the I/M System Status will update to YES, indicating a determination was made, even if all of the other tests for that system have not run.

CONDITIONS FOR RUNNING

HO2S Bank 1 Sensor 1 and Bank 2 Sensor 1

* The engine speed is between 500-3,000 RPM.
* The engine run time is less than 3 minutes.
* The mass air flow (MAF) is between 4-30 g/s.
* The battery voltage is between 9-18 volts.

HO2S Bank 1 Sensor 2

* The engine cold start is determined.
* The average MAF during warm-up is less than 30 g/s.
* The battery voltage is between 10-18 volts.

DIAGNOSTIC AIDS
If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the service information for an indication of why the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning ON, may cause the test to abort.
Was this
answer
helpful?
Yes
No
Saturday, June 11th, 2011 AT 2:49 PM

Please login or register to post a reply.

Recommended Guides