2007 2.4 140HP, DTC P0299 and P1103

[Vikane]

Have had these DTC's coming up for the second time.

P0299 Turbo/super charger underboost
P1103 MAF Sensor in range, but higher than expected

Can anyone tell me what are causing these ? Is it the MAF sensor itself, or ?

[loot]

Mm that's confusing, turbo underboost suggests either a boost leak or egr stuck open(but you'd expect more egr codes possibly)
Maf reading higher suggests erg blocked (although I've never seen range lower than expected, so could that mean that the range being higher could actually mean the range scale whether higher or lower? )

Have you checked the electronic actuator on the turbo, they can fail.
What diagnostics have you got? If a good 1 can you do a turbo test? Can you check the rod and circlips are functioning.
Get someone to press the throttle and you look to see if the vnt rod is moving.
Clear codes and see if they return, either straight away or after a good run,

[Vikane]

Thanks for Your reply loot

The EGR was replaced a few months ago after I got a couple of other DTC'S, no problems after that, until this.
At the same time I also checked the actuator and rod movement, it seems to be working fine.

I have noticed that the engine misfires from time to time, but haven't been able to notice the circumstances, or engine rpm.

I have an Autel tester, don't think I can do this turbo test With this, but will look into it.
When the engine light came up, I stopped at the first service station since I have the Autel tester With me, I immediately read out the codes, and then deleted them, they haven't come back after about 150 miles of driving after that.

[Vikane]

I have replaced the MAF, but it seems that the problem is still there, codes hasn't come up yet.
Have noticed that the engine has a slightly misfire around 2-2500 rpm, and the engine is hunting a bit, specially when cold. What could cause this ?

[Vikane]

DTC came up again, now also P0234 Turbo over boost condition.
Have decided to replace both pressure reliefe valve and suction control valve, hope this helps.

[andycam960]

Did the replacement of the suction control valve & PRV fix the issue, mine has the same DTC and occasionally it will hesitate when driving.
It’s also struggling to start, so changed the batteries & glow plugs
Andycam960

[loot]

Did the replacement of the suction control valve & PRV fix the issue, mine has the same DTC and occasionally it will hesitate when driving.
It’s also struggling to start, so changed the batteries & glow plugs
Andycam960

Hesitation will be egr/injectors/boost i think.

Ids session needed and injector leak off test.

[knobby1]

A duff EGR will cause "overboost/underboost" codes along with MAF & MAP codes.

Lord Knobrot

[andycam960]

Fixed - Purchased a good scanner and it came up with crank sensor. Replaced the crank sensor shes now running fine.

After talking to the dealer he suggested that we check to see if the heat-shield is fitted as this tends to cook the sensors over time causing the problems.

I found the heat-shield in the garage we had forgot to put it back on when we changed the gearbox last year.

Everything has its place an purpose.