Hi there my mate has a polo pacific 1.9 tdi 2008 which has driven 239,000 km. He got a check engine light and flashing glow plug light. Other than that the car is running perfectly. He took it to a local mech who put the obd on it. Strangely the lights disappeared now but the Current obd code is P0727 which is engine speed input circuit which I assume is crank sensor.

the mechanic is a nice guy but not a diesel specialist. Suggested changing the crank sensor - the part from Vw is around $160 and he reckons around 4 hours labour as you have to remove the oil filter to get to it. I don’t have access to a workshop manual to verify that so I wondered if anyone could look it up for me. It’s my mates car and he only paid around $3k for it. He doesn’t have much cash so I’m trying to reduce risk for him. What I’m worried about is he’ll spend $700-$900 relaxing the sensor and it might be something else. The mechanic also suggested an auto electrical guy who would check the cabling (ouch sounds like 3 hours of expense).

any advice or thoughts? My friend will be happy to pay, but I am just wondering if we can find someone who knows these models really well to reduce the chances of doing expensive work that might not fix it.