P1421

P1421 Cold Start Control

Description
ECM controls ignition timing and engine idle speed when engine is started with prewarming up condition.
This control promotes the activation of three way catalyst by heating the catalyst and reduces emissions.

On Board Diagnosis Logic

P1421:

DTC Confirmation Procedure

NOTE:
- If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.
- If DTC P1421 is displayed with other DTC, first perform the trouble diagnosis for other DTC.

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V at idle.

With SDT
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Select "Data list" mode with SDT.
4. Check that the "COOLAN TEMP/S" indication is between 4 °C (39 °F) and 36 °C (97 °F)
If "COOLAN TEMP/S" indication is within the specified value, go to the following steps.
If "COOLAN TEMP/S" indication is out of the specified value, cool engine down or warm engine up and go to step 1.
5. Start engine and let it idle for 5 minutes.
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to [P1421 Cold Start Control].

With GST
Follow the procedure "With SDT" above.

Diagnosis Procedure

Step 1-5:

Step 5 (Continued):