In short :
Is it usual for both O2 sensor (oxygen sensor) to fail together?
Or could it be due to to other faults that the ECM reports both 02 sensor failure ?
If OBD give the following error:
P0131, P0137, P0339
What does it implies? all 3 items are faulty or could it be due to other components ?
P0339 indicate crackshaft posting sensor A – which sensor is this as there are two in the CERATO (part 39138 & part 39250A)
Here is the whole story.
Firstly (no CEL check engine light came on)
I was experiencing the following:
Car stall at traffic light, when about to move off, have to crank a few times to start.
Stalling only happen at low and idle speed.
Car can start easily on cold start, crank one time it will start, can start even when aircon if left turn on ( so cold start is no issue).
When car is driver for 10 mins or so, after that parked and switch of engine. Wait 5 min and try to start engine, will have to crack a few time to start.
Thus like warm start is having problem, cannot start engine easily have to crank a few times.
The stalling problem continues and stall more frequently when engine is warmed. Have to turn of aircon in order to start (during warm start or when stall at traffic light).
Cold start of engine no problem.
Turning off the aircon seems to help a bit during warm start as I need not crank so many time to start engine.
Turning off aircon also tends to cut down the number of times the car stall
There is once I drove from Changi to Bukit Merah, the car stall even when aircon is off, and I noticed a change in the engine exhaust sound, a bit more “piak” “piak” sound,
I think could be one piston not firing or misfiring (not sure). Will misfire cos CEL to light up ?
After parking and turn off engine for an hour, all the sound was gone and car was ok with aircon turn off (dare not turn on cos afraid of stalling on highway)
As it was time for car servicing, I thought may be the issue could go away after the servicing. So went to Autobac change engine oil, change filter, change spark plugs to denson iridium, flush power steering fluid.
The problem did not go away.
A few days later while driving to the mechanic to check, on the way to the mechanic, the CEL light came on.
Mechanic use his OBD reader and check read the OBD codes to be
Mechanic only interpreted P0131 and P0137 and wasn't sure what P0339 is as his reader did not state what is P0339.
P0131 and P0137 indicates faulty oxygen sensor, mechanic quoted SGD$180 each plus $80 for installation
Did not go ahead with the installation, google and found the P0339 indicate crankshaft posting sensor A circuit.
"low battery voltage or a weak starter can can trigger a Crankshaft Position Sensor code. Before replacing any parts, recharge or replaced battery."
During my last servicing, I was told the battery did not pass the test and was told to change. As battery was last change was 3.5 years ago, so I change to a new 65AH battery today.
Reason is unlikely for 3 sensor falling at the same time ….could it be due to battery causing all this ?
After changing the battery, the CEL light did not go off as I have no OBD reader to clear the CEL light.
I ordered the OBD reader to clear the CEL lights online from oversea but think it will take 2 to 3 weeks to reach me.....
Any one could help to give me some advice on what could be the fault?
I have already did the following:
Clean the idle air control valve, clean the air intake valve or throttle.
Took out one of the crankshaft position sensor (39318) and check wiring ok