Colin123
Member
I have an early T6 (Feb 2016) CAAC engine 140 bhp with about 42k miles. It went into the garage last week as it was running rough with the coil light flashing followed some time later by the engine management light. The garage said it was a crank shaft sensor and had the van last week. I've been away and am waiting to hear from the garage on Monday what they actually did/didn't do - as it now has different symptoms and a code of P0299, (according to my cheap code reader). It runs but very roughly ... sort of stuttering if the revs are low. The garage is an independent with good prices and I've been going to them for a number of years so have no reason not to trust them.
My research on this forum and Dr Google have suggested the P0299 as likely one of the things I've listed below. My question is from those with more engine knowledge than me what are the most likely scenarios and approximate costs please? Would it be better going to the main dealer that looks after my VW Golf on an All-in-one plan? I'm not expecting them to be "better" than my independent ... just maybe more familiar with the T6 and its quirks. I'm near Poole in case anyone has specific recommendations. The EGR was replaced last August. I'm trying to get ahead of the discussion with the garage on Monday morning!
My research on this forum and Dr Google have suggested the P0299 as likely one of the things I've listed below. My question is from those with more engine knowledge than me what are the most likely scenarios and approximate costs please? Would it be better going to the main dealer that looks after my VW Golf on an All-in-one plan? I'm not expecting them to be "better" than my independent ... just maybe more familiar with the T6 and its quirks. I'm near Poole in case anyone has specific recommendations. The EGR was replaced last August. I'm trying to get ahead of the discussion with the garage on Monday morning!
- Boost leaks: This is the most frequent cause, often due to split, loose, or cracked intercooler hoses, clamps, or intake pipes.
- Faulty control valves/solenoids: A malfunctioning N75 (boost pressure regulation) valve or a faulty diverter/wastegate bypass regulator valve is a common culprit in VW vehicles.
- Intake/exhaust restrictions: A dirty air filter, a clogged intercooler, a blocked Diesel Particulate Filter (DPF), or a restricted catalytic converter can hinder proper airflow and cause underboost.
- Sensor problems: Faulty Manifold Absolute Pressure (MAP) or Mass Air Flow (MAF) sensors can provide incorrect readings to the ECU.
- Mechanical turbo issues: Less common causes include worn turbo bearings, damaged turbine blades, or a wastegate actuator that is stuck open or has excessive play.
- Vacuum system issues: Leaks in the vacuum lines or a faulty vacuum pump can prevent proper control of the wastegate.
