1.8 20vt P1296 Error

[Rob_Leon]

Hello everyone,

Quick introduction as this is my first post here. My name is Robert and live in the Netherlands. I drive a 2004 Seat Leon 1.8 20vt which I have now owned for about 4 weeks. I am driving around with the engine warning light on, which gives me the P1296 (Error in Mapped Coolant System) error. I have since then replaced both the CST a Thermostat, but to no avail.. I am kind of running low on ideas which is why I have placed my hopes on you guys (and girls). Does anyone have any idea what can cause the P1296 error apart from the CST/Thermostat. Car itself drives fine, but idles rather rough and has some problems starting with a hot engine..

Kind regards,
Robert

 

[Stuart09]

Possibly a dodgy cts.

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[Rob_Leon]

Possibly a dodgy cts.

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I have already replaced the CTS twice, both times using the green top sensor. Both times the error came back a day later.

 

[Stuart09]

Well it won't be that then. What about the water pump.

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[Rob_Leon]

Well it won't be that then. What about the water pump.

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Have not yet touched that. How does the water pump relate to the P1296 error as I have not heard it being mentioned before.

 

[Stuart09]

Well the code is for a coolant system malfunction so could be a possibility. The water pump has a plastic impeller and is known to break, could be the problem. Hope this helps.

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[Rob_Leon]

Well the code is for a coolant system malfunction so could be a possibility. The water pump has a plastic impeller and is known to break, could be the problem. Hope this helps.

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Thanks for the input, really appreciate it! Just looked through my repairs however and it shows that water pump has been replaced when I bought the car. Error was already present before the replacement was put in..

 

[Stuart09]

How is the temp sitting on the gauge. Is it solid at 90 or does it fluctuate

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[mty12345]

Have you checked the wiring to the CTS?

I'm 99% sure that 2 of the pins feed the gauge on the dash,and the other 2 pins send a signal to the ECU. It's possible that you have a wiring issue on the 2 pins feeding the ECU

 

[Rob_Leon]

Needle does not fluctuate and reaches 90 pretty quick. Remains there for the entire drive which is why im baffled that I keep getting the error. As for the wiring, I have not checked that. Any info as to how I can check for faulty wiring? Thanks again for the replies!

 

[Rob_Leon]

The only Freeze Frame data that my (cheap) OBD2 scanner gives me is the following:



Mode $06 report generated by Torque for Android
================================================

Vehicle VIN: Not present
Vehicle Manufacturer: Unknown
Vehicle Calibration ID: Not present

Unit and scaling information are not supplied with the data from the ECU for this type of vehicle. Consulting the manufacturers service book for this information is recommended.

Test report:
------------------
TID:$01 CID:$05
- Rich to Lean sensor threshold voltage(constant)
Max: 102
Test result value: 10
PASS
----
TID:$02 CID:$15
- Lean to Rich sensor threshold voltage(constant)
Min: 159
Test result value: 180
PASS
----
TID:$02 CID:$17
- Lean to Rich sensor threshold voltage(constant)
Max: 159
Test result value: 72
PASS
----
TID:$02 CID:$19
- Lean to Rich sensor threshold voltage(constant)
Max: 254
Test result value: 39
PASS
----
End of report.


I am not even sure it relates back to the P1296 code though..

 

[mty12345]

No mate, that's all unrelated to it. As for the wiring, unplug the sensor and have a look for any build up of corrosion on the pins. If that all looks good, then can your OBD2 scanner do live data? If so then have a look to see what the temp is doing while you're driving,

 

[Rob_Leon]

No mate, that's all unrelated to it. As for the wiring, unplug the sensor and have a look for any build up of corrosion on the pins. If that all looks good, then can your OBD2 scanner do live data? If so then have a look to see what the temp is doing while you're driving,

I though it might be because of incorrect air to fuel ratio due to the ECU recieving wrong temperatures, but that was just a guess. As for the coolant temperatures while driving. They seem to fluctuate between 93-96 degrees. I will check for corroded pins as soon as I can thanks! What is the best way tot remove the corrosion? And any tips on preventing said corrosion in the future?

 

[mty12345]

If the gauge stays at 90C and the actual temp is staying around 90 then thats all as it should be. I can't understand why you would get a code.

When you clear the code, how long before it comes back?

 

[Stuart09]

If it was anything to do with the fueling it would probably throw a code for rich or lean fuel. It must be connected to the cooling system if the temp is stable. Thermostat will be fine. Could be that the temp sensor is faulty are they genuine sensor's or eBay special.

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[mty12345]

That code can only really be the CTS or thermostat. http://wiki.ross-tech.com/wiki/index.php/17704/P1296/004758

Best thing to do is clear the code, and then if it comes back see if you can get freeze frame data for it. That should give the temp when the code was triggered.

 

[Rob_Leon]

If the gauge stays at 90C and the actual temp is staying around 90 then thats all as it should be. I can't understand why you would get a code.

When you clear the code, how long before it comes back?

It throws a pending code almost immediately. A couple of starts later the engine management light shows itself.

 

[Rob_Leon]

If it was anything to do with the fueling it would probably throw a code for rich or lean fuel. It must be connected to the cooling system if the temp is stable. Thermostat will be fine. Could be that the temp sensor is faulty are they genuine sensor's or eBay special.

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Temp sensor has been replaced twice to exclude that. Both times for a green tip one from the dealer. Both times the error almost immediately returned (same or next day).

 

[mty12345]

That's a strange one. Is the thermostat definitely ok and not stuck open? When driving at high speed and off the throttle( down a big A-road hill etc) does the temp drop off?That's usually the cause of this code, if that's not sticking open then i'm out of ideas. You'll have to take it to a VAG specialist/dealer i guess.

 

[Rob_Leon]

That's a strange one. Is the thermostat definitely ok and not stuck open? When driving at high speed and off the throttle( down a big A-road hill etc) does the temp drop off?That's usually the cause of this code, if that's not sticking open then i'm out of ideas. You'll have to take it to a VAG specialist/dealer i guess.

We dont have hills here in Holland sadly, but during long commutes the temperature remains constant. I have logged my daily commute today and will try to post it when i get back from work. I have taken the car to the dealer already, which were as baffled as the rest of us.. Will keep you updated!