1.4 16v bby epc 17961 & 17604

[ruasonid]

Replaced the water pump and timing belts but forgot to disconnect the battery. Coolant is low as I was unable to refill properly without the engine up to operating temp (stat open). Throttle body was removed for inspection.

Engine started up immediately and ran a couple of mins before the EPC lamp came on. Detected codes 17961 & 17604 using a code reader. Engine would not start. If I reset the codes engine will start and stop again with the EPC lamp and same codes. While the engine is running it will not idle at all and sounds rough at low rpm (have to keep revs up around 2000rpm to avoid stall). Engine was running OK before.

17961 - Barometric / Manifold Pressure Signals (something about implausible correlation)

Fault Location:
Manifold Absolute Pressure (MAP) Sensor (G71)/Barometric Pressure (BARO) Sensor (F96) - Range/Performance Problem

Possible Cause:
Intake/exhaust leak.
Exhaust Gas Recirculation (EGR) system.
Evaporative Emission (EVAP) Canister Purge Valve (N80).
Throttle control unit.
Wiring.
Manifold Absolute Pressure (MAP) Sensor (G71).
Barometric Pressure (BARO) Sensor (F96).

17606/P1198 - Oxygen (Lambda) Sensor Heater Circuit: B1 S2: Electrical Malfunction

Possible Causes
Failed O2 sensor heater circuit
Wiring Harness issue
Failing ECM



Any suggestions please as to how I can diagnose the cause?

 

[mty12345]

Hi mate.

Not familiar with the 1.4, but if it's a throttle without a cable then you probably need to do a alignment procedure with VCDS the same as on the 1.8turbo's. This will cause EPC light and IMO possibly the stalling you describe.

which code do you have for the lambda? is it 17604 or 17606 as your post says both and one is for the front sensor and one for the rear.

What are the codes relating to the EPC? As none of those are EPC codes....Can you post up all codes you have please.

17961 code. That means that when the engine isn't running, the 2 air pressure sensors (one in the intake manifold, and one for outside air) don't give the same reading. I would guess that you haven't plugged one of them back in, or knocked the connector on one when doing the water pump.

 

[ruasonid]

That is very helpful, thank you.

It is a throttle without a cable.

The two codes are 17961 and 17604.

I did not see any other codes, only that the EPC lamp came on. I could be missing something as I'm only using a generic code reader which plugs into the OBD port.

I know where the sensor is in the intake manifold so easy to check that. As for the other one ("outside") I'll need to located it. It certainly seems a possibility that I dislodged something.

 

[mty12345]

You're welcome mate.

It's always said that you need VCDS to realign the throttle body. However I noticed a couple of days back, that when the battery is disconnected for 20/30mins, that my engine performs the realignment when it's reconnected and the ignition is turned to position 2 without starting the car. If you don't have access to vcds and you have the radio code, then it may be worth disconnecting the battery and then trying that to see if it performs the auto alignment.

IMO niether the 17961 or 17604 should make the car either fail to start, or stall. So i think the issue is EPC related. I will look up your car on elsawin and see if i can find where the barometric sensor is, just so you can get that sorted for the 17961.

17604 is the heater element of the front O2 sensor before the cat. Again could be the connector or maybe an earth point.

Edit what year is your car mate?

 

[ruasonid]

It is a 2002 model.

I heard a similar story about the throttle body adaptation without VCDS. Some say it is just the throttle body actuator movement after power is reconnected that an alignment routine. Not sure.

Also heard that the MAP sensor in the inlet chamber is the primary sensor and the other sensor is in the ECU itself. Not sure if that is correct or now?

 

[ruasonid]

Forgot to say that after changing the water pump refilled coolant to the level indicator. After cranking the engine the level dropped and put on the indicator lamp on the instrument panel. Refilled to the level and the lamp went off.

Before the above I noticed the plugs were dry and whilst the engine would start it would not idle or run (error lamp/codes as previously described).

Battery was low (indicator on instrument panel) so put on charge.

Reset/adapter throttle using VCDS.

Tried to start and it would not fire. Checked the plugs and they were wet. Possibly fuel supply was enabled again after coolant was added?

All plugs sparking but engine would not fire up. Seems to flood again as plugs were wet once more after drying out.

No error codes or warning lamps.

Any ideas?

 

[mty12345]

Yeah it can't find mention of that sensor in elsawin, so maybe it is in the ECU??

That's really weird mate, If you have fuel and you have sparks then it should fire.... Have you scanned it with VCDS as that might throw some sort of code that generic OBD2 isn't picking up.

Not familiar with the 1.4litre, did you have to take timing belt off to do the pump? If so is the timing 100% right?

 

[ruasonid]

There were error codes before, possibly appearing after it fired up.

This time round no error codes although it won't start (despite fuel and sparks).

Have revisited the timing belt and can not see anything out of place. However, I am not 100% certain the cams did not move when I took the belts off. However, I would have thought that one sprocket out of line would be obvious in that the locking tool would not easily fit or be horizontal.

Have asked a VW specialist to take a look at it since I am out of ideas and time.

Thanks for your input will feedback later.

 

[mty12345]

Goodluck with it mate, and yeah i will be interested to know what it turns out to be.

 

[ruasonid]

Unfortunately timing was out and some valves got bent. Had them replaced and back on the road. Must have made a mistake with indexing the crank/cams.

 

[mty12345]

Oh right, soz to hear that. At least you've got it sorted now mate.