P38A Bank 1 too lean

kermit_rr · Mar 7, 2020

Out tonight and up pops bank 1 too lean. Have a look and the fuel trim is max at 25. Another code saying no activity on o2 sensor bank 1!! Not at all annoying!! How can it decide it's running too lean if it also sees no activity from the o2 sensor? Isn't it supposed to go to default map?
Obviously i need to sort the o2 sensor, but are the 2 related or coincidence?
No engine light and engine seems to run smooth, even idle but possibly down on power a bit and mpg a bit down
Thanks

Henry_b · Mar 7, 2020

Look at live voltages the O2 sensors should be going from between 0-5v if it is stuck what usually happens when they die is they'll give 0V which the ECU reads as lean so it cranks the fuelling up to make it richer which causes MPG and slight running issues etc.

kermit_rr · Mar 7, 2020

Cool I'm guessing that's what the 'no activity' means. Forgot the code number!!
Something to do tomorrow, which probably means it's going to rain all day

kermit_rr · Mar 7, 2020

Bank 1 is passenger/air filter side?

Henry_b · Mar 7, 2020

bank 1 is the "odd bank" so passenger side..

kermit_rr · Mar 7, 2020

Thanks

RangeRoller dt · Mar 7, 2020

If you swap them over and other bank goes lean you will know if/which is duff

Henry_b · Mar 7, 2020

RangeRoller dt said:
If you swap them over and other bank goes lean you will know if/which is duff

Live data will tell ya..

kermit_rr · Mar 7, 2020

I've always had codes for heater circuit inactive, even when i put a new sensor on. Any ideas what i should be looking for? Easy enough to figure out if the heater element in the sensor works so I'm guessing there must be a common wire/connector somewhere for them both not to work?

Grrrrrr · Mar 8, 2020

RangeRoller dt said:
If you swap them over and other bank goes lean you will know if/which is duff

Just getting 1 sensor out can be a PITA. Both of them doesn't bear thinking about.

Might require some heat to get it out.

kermit_rr · Mar 8, 2020

Sensor out and seems to be working, getting a voltage reading when it's hot!.
I suppose now i have to double check and swap them both over

Connectors in the plug look ok so I've no clue where to start if the fault doesn't move to bank 2

kermit_rr · Mar 8, 2020

Swapped the sensor and the problem moved! Answered my own question! Not sure why i thought it was working ok. Will double check the connector

Henry_b · Mar 8, 2020

Are the voltages fluctuating or is it sat at a particular value?

Grrrrrr · Mar 8, 2020

kermit_rr said:
Swapped the sensor and the problem moved! Answered my own question! Not sure why i thought it was working ok. Will double check the connector

Looks like they might have been out before if they're that easy to shift.

kermit_rr · Mar 8, 2020

Henry_b said:
Are the voltages fluctuating or is it sat at a particular value?

Now both swinging like pendulums!! Result

kermit_rr · Mar 8, 2020

Been a blast to clear out any soot from running too rich and both upstream sensors come back with no errors! Engine running lovely, first time ever!!

Now back to the gearbox thread...

Henry_b · Mar 8, 2020

A good result.

Grrrrrr · Mar 8, 2020

kermit_rr said:
Now both swinging like pendulums!! Result

Dodgy connection or broken wire now touching again?!

Henry_b · Mar 8, 2020

Grrrrrr said:
Dodgy connection or broken wire now touching again?!

The Voltages should be going up and down between 0-5v what you don't want to see is a fixed figure that doesn't change

kermit_rr · Mar 8, 2020

Grrrrrr said:
Dodgy connection or broken wire now touching again?!

Possibly

P38A Bank 1 too lean

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