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04 Passat. Got A CodeIn The Past Which Suggested A New Coolant Temp Sensor Was In Order.

Finally got around to replacing it and I got a p0118 "coolant temperature sensor input too high". Also, after the install my temperature gauge on the dashboard stop working.

I have an awm motor so getting it out and replacing it was a pain in the ass, it had no ring on it but I didn't replace to clip, do you think I botched the installation?

The Code I Had before Wasnt P0118, It Was A "CooLing SysteM Performance" Code (Forgot The Number). the cooling system performance code was fixed by the new install, but theP0118 Popped Up After The Cts Replacement.

( sorry for the retarded capitalization errors, My phone does that for some reason)
 

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I have an awm motor so getting it out and replacing it was a pain in the ass, it had no ring on it but I didn't replace to clip, do you think I botched the installation?
Probably. Check the wiring and connector to the CTS. If there was no "O" ring on the CTS it would have been leaking, make sure you don't have 2 "O" Rings on there now.
 

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my phone messed up that. I meant I had an o-ring on the new sensor so I replaced the o-ring but I did not replace a clip
 

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You might have got a bad sensor. That happens sometimes. :(
Unplug the connector at the sensor and check the wires and the pins to be sure nothing got yanked apart or bent.
When you plug it back in make sure it seats completely.

The cooling system performance code might be a problem with the thermostat. If this is the case, that code won't reappear till you get the coolant temp sensor functioning again.

It's OK to reuse the old clip if it's in good condition. This shouldn't effect the electrical operation of the sensor and cause your current problem.
 

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digging an old thread up here.
So I just got this code for the first time after I was elbow deep into my ATQ (2.8L 02 GLX 4mo Wagon 133k mi).
I thought I had a coolant leak at the front of the engine from the connection to the hard pipe that is under the intake manifold.
Before I put everything back together (after replacing the lower radiator hose with the sensor housing and the to/from hoses to the aux pump) I tested the system to see if there are more leaks.
I heard air escaping from the ECTS seat. the ECTS is pretty new (ordered 1/30/19), new o-ring and clip too. with a little pressure on the ECTS with a finger, I could stop the leak. I fashioned a second slip to just add a little thickness to the regular clip. I made the clip out of an old piece of brake pad slider.

I am wondering did I screw up the grounding of this somehow and now I am getting errors? Not easy for me to reach in there and remove the shim (and impossible to put back without removing a lot things just to get access. at a minimum the snorkel and the hose that goes to it from the MAF.

98174


98175
 

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I am wondering did I screw up the grounding of this somehow and now I am getting errors?
I think that sensor is just 2 thermistors (resistors that change resistance based on temperature). As such, it shouldn't be grounded directly to the engine block. I doubt the shim caused the issue but if it was leaking there - for whatever reason - and coolant got inside the plug, that could cause a problem.

Is there a single o-ring there? Sometimes the old o-ring or part of it gets stuck in place and that can screw up the seal of the new o-ring. In any case, it shouldn't leak obviously....
 

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It looks like the connector is broken in that last picture. If you are getting codes, I suspect that is the issue. The wires are not being held in place, so you get a bad connection.

Smart thinking to add that shim, saved a lot of work.
 

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Just to make sure I'm reading your post (#5) correctly and interpreting the pictures correctly...

The coolant temperature sensor is at the rear of the engine. It consists of two independent thermistors, one for the ECM, one for the instrument cluster (gauge, etc). Each thermistor will measure a few K-ohms, depending on temperature.

The physically similar sensor in the lower radiator hose is two normally open temperature switches, one for low speed radiator fan, second for high speed (so, different trip temperatures).

Be sure you have the correct sensor in the correct location.
 

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I think that the sensor is just 2 thermistors (resistors that change resistance based on temperature). As such, it shouldn't be grounded directly to the engine block. I doubt the shim caused the issue but if it was leaking there - for whatever reason - and coolant got inside the plug, that could cause a problem.
yes, there are two sensors in there. when I replaced this one last year I tested the old and new ones and found that 1 of the 2 sensors in the old one was bad (used a multimeter and hot water). thus the previous owners starting in cold weather issues. it was 6 degrees when I left my office last night and it started fine...

Is there a single o-ring there? Sometimes the old o-ring or part of it gets stuck in place and that can screw up the seal of the new o-ring. In any case, it shouldn't leak obviously...
Oh, it was leaking there. I didn't think it was, which is why I went through all that work of pulling off the intake manifold and was about to take the whole pipe off when I realized the connections that should be wet, if there was a leak, were dry. when I tested the system I heard air from the ECTS seat, and when I pushed down on the ECTS in the back, the air stopped.
I also cleaned the crap out of the hole, replaced the less than one-year-old o-ring as well. there can only be one [o-ring]. :)

It looks like the connector is broken in that last picture. If you are getting codes, I suspect that is the issue. The wires are not being held in place, so you get a bad connection.
The connector has been that way for at least 11 months. does p0118 only have to do with the back ECTS or the front one connected to the lower hose? or is there no way to tell without testing each of them?

Smart thinking to add that shim saved a lot of work.
not really, see above...in an unheated garage, in VT, this week.

The coolant temperature sensor is at the rear of the engine. It consists of two independent thermistors, one for the ECM, one for the instrument cluster (gauge, etc). Each thermistor will measure a few K-ohms, depending on temperature.
Correct. The rear one was replaced last year due to the issues (cranks but doesnt start until the 20th try in cold weather) that were told to me when I adopted the car. Solved that issue perfectly.

The physically similar sensor in the lower radiator hose is two normally open temperature switches, one for the low-speed radiator fan, second for high speed (so, different trip temperatures).
Be sure you have the correct sensor in the correct location.
The one on the lower radiator hose in front of the engine was removed to replace that hose and then it was put back. it is still connected.
again is p0118 specific to the rear ECTS or not?
also given the dash temp gauge doesn't move right now and you are telling me the front one doesn't feed the dash, I do not think the issue is the front one.
Also I haven't gotten the cap to blow off, so I think the fans are kicking on when they should.
 

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The physically similar sensor in the lower radiator hose is two normally open temperature switches, one for low speed radiator fan, second for high speed (so, different trip temperatures).

Be sure you have the correct sensor in the correct location.
So this (blue, PN:8D0959481B) is the one on the lower radiator hose in the front of the engine:
98180


This (green, PN:059919501A) is the one in the back, which was leaking:
98181
 

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The green one at the back feeds the OBD and dash reading is a sensor.
The blue one is a switch; not so much a sensor. It is the one in the lower rad hose. It does not report a reading to the ECU but rather energizes one or both wires related to fan speed to the fan controller.

Yes, the code pertains to the one at the back of the head. Since you have no temp reading on the dash, that is a classic sign of failure of the green sensor at the back, even if there are no running issues.

Maybe, just maybe, the cracked/broken plug is rearing it's head as the culprit this time. Maybe probe the appropriate wire for the dash signal and determine if you are getting a good connection on the sensor.
 

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Since you have no temp reading on the dash, that is a classic sign of failure of the green sensor at the back, even if there are no running issues.
But it is feeding the CCM (OBD) or else I would have the starting issue, no? or does p0118 mean that CCM/OBD does not get signal? My notes show that I was showing a P0117 before I replaced the ECTS last year.

Unfortunately, I won't be able to try reseating or playing with the connector until Sunday at the earliest. No garage. its 20 degrees outside and I am at work today and tomorrow during any daylight.

I did check and I did plug everything back in. Maybe it's not in all the way, as the first thing listed for P0118 when I just did some more research between P0117 and P0118 is "A bad connection at the sensor"

Really hoping it will resolve when I reseat it. if that doesn't work, on Monday I will hit the scrap yard and grab a bunch of 4 pin connectors and replace it.
 

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Not the CCM, the ECU; the module that controls engine operation with fueling ans such. The 2 part sensor sends signals to the ECU and the temperature gauge. Two separate sensors in one housing. One part can fail while the other is fine. I've had it both ways on two separate cars. One car, the temp guage went to zero with no running problems (hooked up a scanner and it read the temperature just fine) and the other failed on the ECU side of sensor and had hard start problems. The code is telling you what sensor is at fault; the G62 sensor. That is the location of #5 in the diagram here.
98183
 

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Not the CCM, the ECU; the module that controls engine operation with fueling and such.
Sorry, that's what I meant.
[/QUOTE]

The 2 part sensor sends signals to the ECU and the temperature gauge. Two separate sensors in one housing. One part can fail while the other is fine.
Yes, I am aware of this. The one I replaced had failed on the ECU side.

I've had it both ways on two separate cars. One car, the temp gauge went to zero with no running problems (hooked up a scanner and it read the temperature just fine) and the other failed on the ECU side of the sensor and had hard start problems.
So given that:
1) I am not having hard start issues (It had code p0117 when it did)
2) I am getting a zero reading on the dash (and constant 40 degrees reading from torquepro app)
3) getting code p0018

Do the above indicate that the dash side is dead, not the ECU side. Would a dead dash side give me all these issues and the code? or does that mean that both sides are shot...if so, why am I not having hard start problems in cold weather? This is why I am very confused.

The code is telling you what sensor is at fault
Copy. Yeah, I know where it is. I just can't get to it until Sunday to try to reseat the connection.
 

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Do you have a code reader (eg VCDS) that can read the two outputs of the CTS? It sounds like a bad connection or bad wiring but the G62/ECS is a part that seems to fail more often than it should. Is the replacement part OEM or aftermarket?

Having one output fail with the other not failing is very common so I wouldn't put much stock in the fact that it starts well. It could just be bad luck that first one, now the other side has failed. Or bad wiring/connection, etc. I'd think the dash is the least likely part to fail although I suppose that could be the problem too.
 

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Do you have a code reader (eg VCDS) that can read the two outputs of the CTS?
Negative. I am so tight right now its not even an option. just the 5 dollar bluetooth knock-off variety.

It sounds like a bad connection or bad wiring but the G62/ECS is a part that seems to fail more often than it should. Is the replacement part OEM or aftermarket?
Yeah, it was replaced with an aftermarket one 11 months ago. I am leaning towards a wiring issue at this point given the collective knowledge being shared. The company is sending me out another one anyway as they offered a one year warranty. I sent them a screenshot of the p0118 code and my order number from 01/30/19, they said no problem, but that will be a few days.

Having one output fail with the other not failing is very common so I wouldn't put much stock in the fact that it starts well. It could just be bad luck that first one, now the other side has failed. Or bad wiring/connection, etc. I'd think the dash is the least likely part to fail although I suppose that could be the problem too.
I didn't mean to imply my actual dash was the issue. If it was the actual dash, I wouldn't be getting the p0118 code.
 

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Negative. I am so tight right now its not even an option. just the 5 dollar bluetooth knock-off variety.
AR, this is a great time to get a better job. You’re clearly a smart, hard worker and dedicated employee. Find something that rewards you more for it. And now I will MYOB. :)
 

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It could very well be wiring. P0117 and P0118 both have a bad wiring connection as a possible cause.

So given the broken clip on the 4 pin connector to the ect sensor, when I had put it all back together I had taken the harness for the ects and the passenger side something sensor over the powersteering pipe. I guess it had pulled itself up and lost contact.

I took the tube after the maf and the snorkel off then routed the wire under the PS pipe and no more p0118, dash shows proper temp, torque app shows ect readings.

I have run the diagnostics on the climatronic unto and only get the 513 gateway error. While in various conditions all the live readouts from the climatronic units all make sense... But I'm still not getting consistent heat. There are no leaks in the cooling system as it holds pressure using a pressure testing kit from Amazon.

The only thing that I can think is I need to Bleed the system but I am all outta thoughts. Shy of that I guess I need to save up and get a vcds and start testing all the vent doors... But there was never a problem with them. Plenty of flow through the core in both directions... So gotta just be air in there.
 

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That would be the CCT adjuster that you moved the plug on. Hopefully rerouting the CTS wires will keep the light out, but you may look to replace the connector when the weather gets nicer.
 
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