Bletourneau
Member
Hey guys. Been a long time since I've been in a tdi and been on these forums. I've had a 03 golf tdi and a 2000 Jetta tdi in the past. I have vcds. My dads been driving these cars for the better part of 20 years so I'd like to think we are fairly capable when it comes to them. Anyways enough of the back story.
I recently started driving one of my dads beater cars, car in question being a 2000 Jetta tdi 5 speed. ALH engine code. Using it as a commuter for back and forth to work.
The engine light was on when I started driving it and it was throwing a code for temp sensor p1256 and for the glow plugs originally. I stripped apart the glowplug harness, cleaned all the connections, re did the main harness power wires , cleaned all the plugs and benched tested them via battery and multimeter, and reinstalled everything and all was well in that department.
The car was showing no heat on the dash but via vcds in measuring blocks would show what I assumed to be fairly accurate coolant temperature. Changed out the temp sensor last night with a green and brass bodied coolant sensor. Reinstalled everything and started it up. Dash hest gauge is now working and will go up to center 90 celcius after a highway run without issues.
However the issue I'm having now is that vcds will only show a max coolant temp of 25-30 degrees celcius, even right after the highway drive.
The other odd thing was right after the highway drive, both fuel temp and coolant temp were reading identical temperatures at 24.3 degrees celcius.
I'm also 99% sure that even with the coolant temperature sensor unplugged, the temp remained the same via vcds. I was under the impression it will show a maxxed out minimum temperature and will default the plugs to cycle for 20 seconds, is this correct? I can confirm the other 1% question tomorrow when o have a chance to work on the car again.
Right now it seems regardless of temperate , the glow plugs will cycle for about 10 seconds. The car seems to fire up and idle fine without issues. Previously before the sensor change the car would start up and high idle at about 1500 give or take for a quick half second then come back down to 950 rpm give or take.
Just looking for advice at this point. Should I assume the sensor is good and start looking at wiring harnesses, or assume that I maybe got a fault temp sensor which is possible.
Thanks in advance
I recently started driving one of my dads beater cars, car in question being a 2000 Jetta tdi 5 speed. ALH engine code. Using it as a commuter for back and forth to work.
The engine light was on when I started driving it and it was throwing a code for temp sensor p1256 and for the glow plugs originally. I stripped apart the glowplug harness, cleaned all the connections, re did the main harness power wires , cleaned all the plugs and benched tested them via battery and multimeter, and reinstalled everything and all was well in that department.
The car was showing no heat on the dash but via vcds in measuring blocks would show what I assumed to be fairly accurate coolant temperature. Changed out the temp sensor last night with a green and brass bodied coolant sensor. Reinstalled everything and started it up. Dash hest gauge is now working and will go up to center 90 celcius after a highway run without issues.
However the issue I'm having now is that vcds will only show a max coolant temp of 25-30 degrees celcius, even right after the highway drive.
The other odd thing was right after the highway drive, both fuel temp and coolant temp were reading identical temperatures at 24.3 degrees celcius.
I'm also 99% sure that even with the coolant temperature sensor unplugged, the temp remained the same via vcds. I was under the impression it will show a maxxed out minimum temperature and will default the plugs to cycle for 20 seconds, is this correct? I can confirm the other 1% question tomorrow when o have a chance to work on the car again.
Right now it seems regardless of temperate , the glow plugs will cycle for about 10 seconds. The car seems to fire up and idle fine without issues. Previously before the sensor change the car would start up and high idle at about 1500 give or take for a quick half second then come back down to 950 rpm give or take.
Just looking for advice at this point. Should I assume the sensor is good and start looking at wiring harnesses, or assume that I maybe got a fault temp sensor which is possible.
Thanks in advance
