[hdrewh]

Hi Guys,

'09 E90 LCI 328i. Started up this morning, running like crap, SES light on. Carly diagnostics show 2A1A - Fuel tank ventilation system, and a cylinder 1 misfire (29CD).

Thinking of first replacing the fuel tank vent valve, but would also like to know if that fault could also cause the cyl. 1 misfire.

Thanks in advance.
Howard
BTW I did confirm gas cap is on tight.

[gbalthrop]

Originally Posted by hdrewh

...'09 E90 LCI 328i. Started up this morning, running like crap, SES light on. Carly diagnostics show 2A1A - Fuel tank ventilation system, and a cylinder 1 misfire (29CD). Thinking of first replacing the fuel tank vent valve, but would also like to know if that fault could also cause the cyl. 1 misfire.

Hi Howard,

My interpretation of 2A1A per Bentley's Definitions of that code (3 different ones) is that it refers to the Tank Vent Valve or "Purge Valve" (TEV in INPA & TIS) that opens when the engine is running & warm, to purge the charcoal canister by drawing fuel vapor from the charcoal into the intake manifold. It has NOTHING to do directly with the DMTL "leak test" procedure.

That Tank Vent Valve either opens/closes when and to the degree it should or it does NOT. Before the DMTL Leak Test can be done after shutdown, that Tank Vent Valve has to close. If the valve does NOT close, the DMTL test is NOT performed. I don't know anything about Carly (other than it doesn't seem to give very clear code definitions ;-) but I would want to know if those are the ONLY two codes you have. I can see NO WAY in which they are related. It WOULD be interesting to see the "Freeze Frame Data" for each of the 2 codes to know (1) the mileage at which each of the two codes was saved in DME memory, and (2) the engine conditions, particularly temp & RPM when each was saved.

INPA would allow you to see any codes related to DMTL as well as Tank Vent Valve, and to test operation of each, all by connection to the DME Module. Here are Bentley definitions of 2A1A -- note there are THREE, and two have P-code equivalents:
P0440 | 2A1A | Evaporative Emission System Incorrect Flow
P0441 | 2A1A | Evaporative Emission System Incorrect Purge Flow
2A1A | Fuel Tank Venting Function Fault

If one interprets that Definition literally, "Incorrect Purge Flow" most likely means NO flow when purge should be occurring, or valve butterfly CLOSED, rather than Valve constantly in Open position. My SWAG would be the valve is "normally-closed" and requires voltage to open. Proper test equipment (INPA ;-) should tell you which it is. The valve and its wiring are NOT the easiest to access, being in jail beneath the intake, so using INPA or other proper diagnostic software to read codes, and do Activation of the valve, and see actual position vs. control position, is much easier than trying to disconnect the connector, or remove the Valve for bench testing to see if it opens/closes properly when voltage applied/removed.

I don't have personal experience testing that system, so if ANYONE who does can suggest some practical steps, please advise.

I don't know what diagnostics Carly can do, but if it cannot do the things INPA can do as described above, and you don't want to pay a shop to run INPA/ISTA diagnostics, I would first test the wiring/connector from the DME/DME Relay fuse (F11) to the Valve per this TIS circuit diagram:
https://www.newtis.info/tisv2/a/en/e...-valve/vGwLurz

Here are the "Installation Location" and the "Connector View" for the Connector X6120 which has an Orange wire (Pin #1) from the DME Relay Fuse (F11) and a White/Blue wire from the DME which is the DME-switched ground to open/close the valve:
https://www.newtis.info/tisv2/a/en/e90-328i-lim/SJvtED2
https://www.newtis.info/tisv2/a/en/e...i-lim/HRQlKDEV

I do NOT think the fuse could be bad, preventing operation of the Vent Valve, since the same fuse powers the Crankshaft Sensor, lack of which signal would prevent starting, but might as well check everything:
https://www.newtis.info/tisv2/a/en/e...1-fuse/vCFKEe3

Please let us know what you find,
George

[hdrewh]

Thanks George, great info.
First I replaced the tank fuel tank vent valve,and that code went away but the SES light was still on. I swapped the coil pack of cylinders 1 and 2 and the misfire went to 2, so I replaced that coil pack and all is now well.

Here is more info from Carly:

Faultcode: (0x2A1A) Tank ventilation system function
Faultset 1:
(appeared at: 208584.0km)
calculated air mass:
90.00 mg/stk
Engine speed:
640.00 rpm
engine temperature:
94.50 °C
corrected setpoint flow Tankentlueftung:
0.09 kg/h

Faultcode: (0x29CD) Misfiring, Cylinder 1
Faultset 1:
(appeared at: 210000.0km)
Load value for misfire detection:
19.14 %
engine temperature:
12.75 °C
No-load value for misfire detection:
13.67 %
Voltage accelerator sensor 1 monitoring:
0.70 V



As I look at it myself it seems the fuel tank vent issue happened some time ago, but apparently that does not trigger the SES light because it never came on, so the misfire is what caused the SES light which led me to see 2A1A code for the vent valve. I guess if the coil pack did not go bad I would never have known about the tank vent, and carried on in blissful ignorance.

[335i N55]

I have the same issue with the vent valve and fuse 11 is blowing. Replaced vent valve, code still there. Manually powered the vent valve and it operates. anyone else have an idea? Fuse 11 power anything else?

[xavi718]

Originally Posted by 335i N55

I have the same issue with the vent valve and fuse 11 is blowing. Replaced vent valve, code still there. Manually powered the vent valve and it operates. anyone else have an idea? Fuse 11 power anything else?

Did you solve your problem?