[jimmye4golf]

2002 Passat 1.8t automatic. 190k miles. She said last week her check engine light was on and the car died at an intersection . She said it started back up and drove it for several days before it died again just randomly. I drove the car a few years before she got it and had similar issues. I've put 3 MAF sensors on it and have cleaned them numerous times. I also replaced every vacuum line, both PCVs and all those hoses and the big T At the back of the engine. I did all this about a year ago. I gave it a quick look over and couldn't see anything wrong with it the other day (short on time). I had her take it to Autozone and they pulled P0322, P0420, P0116. The ECT was also replaced about a year ago. I vaguely remember the codes that I had did not really associate with what the actual problems were. Any ideas where to start? Gonna try to work on it this weekend. Thanks in advance for any pointers, tips, shortcuts or advice.

 

[MirceaM]

ESS Engine Speed Sensor. If the car died at the intersection its the Speed Sensor. Had the same problem a couple of years back.

For the hard start It might be the CTS Coolant Temperature Sensor. Thats what P0116 is for.

Both pretty cheap fixes.

 

[Tomvw]

16706/P0322/000802 - Engine Speed Sensor (G28): No Signal
16706/P0322/000802 - Ross-Tech Wiki
This indicates that you might have a faulty ESS or its wiring.

16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold
16804/P0420/001056 - Ross-Tech Wiki

16500/P0116/000278 - Engine Coolant Temp. Sensor (G62): Implausible Signal
16500/P0116/000278 - Ross-Tech Wiki

The ECT was also replaced about a year ago.

Do you mean the CTS (Coolant Temperature Sensor). It or its wiring could be faulty again.


Instead of replacing MAF sensors all the time, test it.
Ross-Tech-Tip - Diagnosing a VW/Audi MAF Failure http://www.ross-tech.net/vag-com/advertising/DiagnosingA_MAF_TechTip.pdf

 

[FrescoGreen01.5]

ESS Engine Speed Sensor. If the car died at the intersection its the Speed Sensor. Had the same problem a couple of years back.

For the hard start It might be the CTS Coolant Temperature Sensor. Thats what P0116 is for.

Both pretty cheap fixes.

^ x2

 

[sirwired]

Start with the obvious, swapping the ESS and CTS, clear codes, and see if the cat code comes back. I think it will (the bad CTS can cause over-rich running, poisoning the cat), and you'll probably need a new one installed. (Aftermarket cats aren't as expensive as you'd think.)

 

[jimmye4golf]

Is there a way to test the coolant temp sensor? I replaced the crankshaft sensor and it ran great. Even my daughter was commenting on how much better it ran. Then 2 days later she calls and says it won't start. She said it acts like it wants to start but wont. I go over there yesterday afternoon and it starts but when you give it a little gas it falls on its face similar to a choke being stuck closed on a carbed engine. Made me think of the MAF sensor so I took it off and cleaned it, put it back together and went and drove it about 15 mins and it ran fine. She calls me this morning and said it would barely start again . Both times it wouldn't start were early in the morning and it was nice and cool. It seems to start ok but still bog down once the outside temp is warmer. Just figured I would test that CTS before I dump a couple of gallons of gas on it a d set it a blaze.

 

[sirwired]

The easiest way is to plug it into an OBD scanner (The free VCDS-Lite with an OBD-USB cable or a Bluetooth dongle with Torque on an Android phone should be fine) and see what it reports the coolant temp at when it's refusing to start.

 

[ylwagon]

Is there a way to test the coolant temp sensor? ...Just figured I would test that CTS before I dump a couple of gallons of gas on it a d set it a blaze.

There is, using a Digital Multi-meter, checking for resistance. While I don't have the pinout and specs at hand, by knowing the approximate coolant temp, you can see if your measurements are reasonable. The CTS is simply two thermally-responding resistors, which have less resistance as the temperature rises. One resistor is for the temp gauge, the other is for the ECU. But besides the resistors themselves, high-resistance at the connector, for instance, can cause the ECU to respond to a hot engine as if the coolant was cold. At the end of the day, these sensors are cheap enough to just install if in doubt.

 

[FrescoGreen01.5]

20°C/68°F is 2.2 to 3.0 kOhms
30°C/86°F is 1.5 to 2.0 kOhms
90°C/194°F is 200 to 275 ohms

The ECM reads between terminals 1 & 3, which are on the left with the two ribs at the top. The other terminals, for the gauge, are probably the same resistance.

Ref Bentley page G24-5

 

[Tomvw]

I believe the sensor for the gauge has a different resistance range.