DTC P0420 THREE WAY CATALYST FUNCTION - Diagnostic Procedure (Cont'd)
EF & EC-7189flowchartCG10, CGA3
Diagnostic Procedure (Cont'd)
Diagnostic Procedure - Steps 4 to 6
1
4. CHECK IGNITION TIMING: Check for ignition timing. Refer to TROUBLE DIAGNOSIS — "BASIC INSPECTION", EC-7053.
2
OK or NG
NG
Check camshaft position sensor (PHASE) (EC-7181) and crankshaft position sensor (POS) (EC-7176).
OK (GO TO 5)
3
5. CHECK INJECTORS: 1. Refer to Wiring Diagram for Injectors, EC-7166. 2. Stop engine and then turn ignition switch "ON". 3. Check voltage between ECM terminals 3, 4, 31, 32 and ground with CONSULT-II or tester. Battery voltage should exist.
4
OK or NG
NG
Perform "Diagnostic Procedure" INJECTOR, EC-7166.
OK (GO TO 6)
5
6. CHECK IGNITION SPARK: 1. Disconnect ignition coil assembly from rocker cover. 2. Connect a known good spark plug to the ignition coil assembly. 3. Place end of spark plug against a suitable round and crank engine. 4. Check for spark.
6
OK or NG
NG
Check ignition coil, power transistor and their circuits. Refer to EC-7228.
See also
EC-7053 · EC-7181 · EC-7176 · EC-7166 · EC-7228