Vento won't start

[anthony--t]

HELP!

The new girl now refuses to start... Gave it a quick scan with VAG-COM:

17978 - Engine Start Blocked by Immobilizer

00282 - Throttle Position Actuator (V60)

Not sure how old these codes are. Had a quick look around and couldn't see anything wrong with the fuses, fuel pump relay etc. Haven't had a GOOD look because I haven't had the time yet. Just thought I'd throw it up here for some suggestions of things to look for. Fuel pump sounds like it's priming engine cranks but won't fire. Previous owner told me sometimes it wouldn't start first time but if you tried again 5 minutes later it would be fine. It's been sitting out the front for 2 days now not moving.

Have had a good look in the bentley manual and searched everywhere, can't find any solid information so I guess I'll just try rule things out depending on what people suggest.

1995 2.0 8v vento if that helps with anything.

Cheers Anthony

[Water Boy]

00282 - Throttle Position Actuator (V60) is because the car is off (engine not running).

And the other thing may be a problem with the key or ignition halo???? (im no expert here)

[anthony--t]

Yeah I fear that it's immobiliser related. Investigating ways to bypass it as I know keys and ecu recoding and all that stuff can get expensive. (lost my step dads mk5 tdi key, set me back $400 for a new one from vw)

[ffoff]

usually with an immobilizer issue, doesnt the car fire, and then die? same as the ignition switch?

[anthony--t]

usually with an immobilizer issue, doesnt the car fire, and then die? same as the ignition switch?

Yeah, that's what I thought. The code has shown up though. Might give it another scan tomorrow see if there's anything new / if the same codes came back.

I bet it's something little and stupid. Just have to figure out what.

[KKK VR6]

Well this is what i think.
disconnect the battery an wait for the ecu to reset, then do a scan.
While waiting unplug the TPS, check if the pins are dirty, give it a blow.
Does it have a alarm ?
Chances are its immobilizer related.

[anthony--t]

Well this is what i think.
disconnect the battery an wait for the ecu to reset, then do a scan.
While waiting unplug the TPS, check if the pins are dirty, give it a blow.
Does it have a alarm ?
Chances are its immobilizer related.

Cheers! Will give that a crack tomorrow while investigating all the other sensors. Hopefully resetting the ecu might trick the immobiliser for a little while.
Pretty sure it doesn't have an alarm.

[jamesdavid]

Hey Anthony,

I m near 100% positive the car will still start regardless, it will run for like 2 seconds, the immobilizer light in the dis will flash and then the car will die.

I would suggest not wasting your time researching ways around it, if its an auto i m pretty sure that the ecu disables the gearbox control unit as part of the anti theft system, it would be a headache to attempt a way around it.

I am at work tomorrow, let me check out a few things, can you shoot me through your vin? and engine code?

I would hazard a guess it may be more related to a cam/crank position sensor (as they can intermittently happen) which sometimes wont throw a code and unfortunately for you an oscilloscope is the only real way to confirm that. At the same time it will crank and have all the essentials for starting but it cant see crank/cam position and wont fire. May also be an engine speed sensor related.

Again, post your vin and i ll have a look at a few things,

Cheers,

James

[anthony--t]

Hey Anthony,

I m near 100% positive the car will still start regardless, it will run for like 2 seconds, the immobilizer light in the dis will flash and then the car will die.

I would suggest not wasting your time researching ways around it, if its an auto i m pretty sure that the ecu disables the gearbox control unit as part of the anti theft system, it would be a headache to attempt a way around it.

I am at work tomorrow, let me check out a few things, can you shoot me through your vin? and engine code?

I would hazard a guess it may be more related to a cam/crank position sensor (as they can intermittently happen) which sometimes wont throw a code and unfortunately for you an oscilloscope is the only real way to confirm that. At the same time it will crank and have all the essentials for starting but it cant see crank/cam position and wont fire. May also be an engine speed sensor related.

Again, post your vin and i ll have a look at a few things,

Cheers,

James

Cheers James! Car is a manual but I agree with what your saying about the immobiliser should shut off the car after it's started and not prevent it.


Really appreciate the willingness to help!

[jamesdavid]

Can confirm car will still start regardless of immobilser fault, in regards to fault;

Fault code 17978 -"Engine control unit blocked" is stored in fault memory, this means: The immobilizer control unit has not released the engine control unit.

So at least you can rule out the immobilser as the no start concern, in regards to the throttle position actuator have you taken off the intake pipe and checked to make sure the throttle plate isnt binding? As you know if the throttle plate is stuck closed no air means no start. I d check that and maybe check power and earth at the throttle motor connector.

From what i can see the connector should have 7 wires but possibly have 8 ports for wiring, earth of the module is pin 7. Pin 1 is the power for the actual motor and pin 2 is the earth for it they should be black and white respectively and larger than the other wires there. So if the throttle valve is movable check your motor voltage readings. From the wiring diagram and my understanding of throttle valves lol, there is a potentiometer also which should have a reference voltage (possibly 5 volts) and signal voltage which will be pin 5 and 8. This allows the ecu to determine throttle valve position based on the received voltage.

Check for continuity between pin 1 and 2 there should be a circuit its a motor after all.

Let me know how you go,

James