I did not have a glow plug warning light on my cluster, but was told a faulty glow plug number three would trigger the engine management light for mass air sensor low circuit 000258. Since replacing the glow plugs, the engine runs smoothly on cold start-up. I have reset the code and it come back. The MAF still have error code 000258, I have cleaned it with spray and it won't go past 3,000 rpm, need a new one?

Edited 18 April, 20251 yr by 43576

12 minutes ago, 43576 said:

I did not have a glow plug warning light on my cluster, but was told a faulty glow plug number three would trigger the engine management light for mass air sensor low circuit 000258. Since replacing the glow plugs, the engine runs smoothly on cold start-up. I have reset the code and it come back. The MAF still have error code 000258, I have cleaned it with spray and it won't go past 3,000 rpm, need a new one?

Hi,

Can you give any further info on the car, such as what engine, how many miles are on it and what sort of journeys you do (distance/speed)?

Octavia Mk2 facelift 2.0TDI PD 140bhp 2009, 91,000 miles, drove the engine is limit 3,000rpm. I do average 20,000 miles per year.

When did the issue first start occuring?

I found that my engine was rough starting in the cold morning about two weeks ago, scanned this. I did not know that I had problem with MAF, the car did go above 3,000rpm. But now won't go more than 3,000rpm after new glow plugs fitted, reset the code 005660 did not comeback, but only 000258

000258 - Mass Air Flow Sensor (G70)

P0102 - 000 - Signal too Low

Freeze Frame

Fault Status: 01110000

Fault Priority: 2

Fault Frequency: 1

Reset counter: 255

Mileage: 148003 km

Time Indication: 0

Date: 2063.14.31

Time: 00:29:55

Freeze Frame

RPM: 1092 /min

Speed: 0.0 km/h

Load: 0.0 %

Duty Cycle: 79.7 %

Bin. Bits: 00001100

Mass Air / Rev.: 435.0 mg/str

Mass Air / Rev.: 0.0 mg/str

005660 - Glowplug for Cylinder 3 (Q12)

P161C - 000 - Open Circuit

Freeze Frame

Fault Status: 01110000

Fault Priority: 3

Fault Frequency: 1

Reset counter: 255

Mileage: 148003 km

Time Indication: 0

Date: 2063.14.31

Time: 00:29:59

Freeze Frame

RPM: 798 /min

Speed: 0.0 km/h

Load: 0.0 %

Voltage: 13.98 V

Bin. Bits: 00001100

Temperature: 15.3°C

Bin. Bits: 10110000

Edited 18 April, 20251 yr by 43576

If you read the measuring blocks for the mass air flow sensor at idle, what reading do you get?

Idle flow is 382 mg/str through the mass, mean anything good or bad? out temperature is 12c.

is there specified and actual values for mass air flow?

if so, ideally you want them to correlate at idle

Edited 18 April, 20251 yr by User2908

?

15 hours ago, 43576 said:

Idle flow is 382 mg/str through the mass, mean anything good or bad? out temperature is 12c.

Indicates there is not a open circuit or dead short to ground in the wiring as you are still getting a reading, id first start by checking mechanically if things are okay, such as a blocked air filter, split or loose piping Behind the mass air flow sensor, most likely the corrugated elbow and the vent hose attached to it (seeing as it may have been removed for glowplugs)

When you cleaned the sensor, did you just clean the contacts on the plug or did you remove the sensor and clean the sensor ports that sit inside the intake pipe?

I have follow your instructions, the 00258 did come back. The mass sensor looks new, I purchased the car a month ago.

1 minute ago, 43576 said:

I have follow your instructions, the 00258 did come back. The mass sensor looks new, I purchased the car a month ago.

So the pipework looks okay (including the small one under the plastic engine cover) + the air filter looks good?

If the air flow sensor looks new it may have been replaced just before you got the car. Its a long shot but wondering if its the correct one thats fitted or why it was replaced. Might be worth checking wiring continuity as well.

Alasdair

5 hours ago, User2908 said:

So the pipework looks okay (including the small one under the plastic engine cover) + the air filter looks good?

New air filter recently, will look the wires loom.

Is maf is good you have egr stuck, or wiring ECU fault.

Edited 19 April, 20251 yr by Blue8793841

The code isn't EGR?

I open the EGR pipe in front of the inlet manifold, grease lumps are blocking the inlet manifold. It looks like the faulty EGR is blocked. Carry out cleaning soon.

To see if the light goes off this time, hopefully.

It blocked badly, since now clear no error. Why does it mention air mass? It has nothing to do with this, it is EGR. Why doesn't it say EGR on the diagnostic tool? It would make my life a bit easier to find the fault?

Holy crap thats well blocked. I thought mine was bad. I hate EGR. I blanked mine on my old toyota lucida as it was the same and very prone to blocking. Who ever thought of recirculating exhaust gases was a good idea was obviously not a mechanic . Glad you got to the bottom of it.

Aladdair

The MAF sensor should show a reduction in the flow of fresh air in proportion to how much EGR recirculation is commanded.

If EGR is very blocked, like yours, then the expected change in MAF reading will not happen.