EC-362
[QG (WITH EURO-OBD)]
DTC P0420, P0430 THREE WAY CATALYST FUNCTION (A/T MODELS)
5.
Set voltmeters probes between ECM terminals 35 [HO2S1 (B 1)
signal], 36 [HO2S1 (B 2) signal] and engine ground, and ECM
terminals 16 [HO2S2 (B 1) signal], 17 [HO2S2 (B 2) signal] and
engine ground.
6.
Keep engine speed at 2,000 rpm constant under no load.
7.
Make sure that the voltage switching frequency (high & low)
between ECM terminals 16 and engine ground, or 17 and
engine ground is very less than that of ECM terminals 35 and
engine ground, or 36 and engine ground.
Switching frequency ratio = A/B
A: Heated oxygen sensor 2 voltage switching frequency
B: Heated oxygen sensor 1 voltage switching frequency
This ratio should be less than 0.75.
If the ratio is greater than above, it means warm-up three way
catalyst does not operate properly. Go to
EC-362, "Diagnostic
Procedure"
.
NOTE:
If the voltage at terminal 35 or 36 does not switch periodically more than 5 times within 10 seconds at step 7,
perform trouble diagnosis for “DTC P0133, P0153” first. (See
EC-218
.)
Diagnostic Procedure
EBS00QNV
1.
CHECK EXHAUST SYSTEM
Visually check exhaust tubes and muffler for dent.
OK or NG
OK
>> GO TO 2.
NG
>> Repair or replace.
2.
CHECK EXHAUST GAS LEAK
1.
Start engine and run it at idle.
2.
Listen for an exhaust gas leak before the three way catalyst (Manifold).
OK or NG
OK
>> GO TO 3.
NG
>> Repair or replace.
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