Diagnostic Aids

Check for any of the following conditions:

• The PCM will not enable the catalyst test until following conditions are met:
  1. The engine speed is within 200 RPM of the desired idle.
  2. The TP is 1.5 percent or less.
  3. The short term FT is -20 to 20 percent.
• The catalyst test will abort if the vehicle falls outside the conditions listed below while the test is running:
  1. The engine speed is within 200 RPM of the desired idle.
  2. The throttle position is 1.5 percent or less.
  3. The short term FT is -20 to 20 percent.
• The catalyst test will abort if the vehicle falls outside the conditions listed below while the test is running:
  1. The engine speed is within 200 RPM of the desired idle.
  2. The throttle position is 1.5 percent or less.
  3. The short term FT is -20 to 20 percent.
• The catalyst test may abort due to a change in the engine load. If this condition occurs, use the scan tool in order to force the cooling fans ON. Return to step  3 in the test procedure.
  NOTE: When using the scan tool in order to force the cooling fans ON, use the next list and previous list soft keys in order to enter the catalyst data list. If the catalyst data list is not entered this way the cooling fan control will be canceled.
• The number of attempted tests is limited to 18 per key cycle.
• More than 6 tests may have to be attempted in order to get 6 completed tests. An aborted test counts as an attempted test.
• If 18 tests have been attempted and if a decision has not been made during this key cycle, turn the key OFF for 30 seconds. Start the vehicle, and perform the conditions for running the DTC, including the 10 minute run time.
• After returning to an idle the HO2S 1 signal may stay rich or lean for several seconds, causing the test to be delayed.
• If the condition is determined to be intermittent, refer to INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.