2000 S70 won't start 9125463 ETC ETM Sacher replacement Topic is solved

[abscate]

Look for 1999 resistance chart as the 99- has a different sensor than the -98

Part 9125463 for 1999-2004 applications

[Rocambolesque]

I just went outside and did the temperature sensor resistance test according to this procedure:
https://www.pelicanparts.com/techarticl ... lacing.htm

I plotted the values for the 99+ sensor in a graph so I could extrapolate for colder temperatures. It's -20C outside today. I guess the coolant in the car should be around that temperature:


Following this, I expect the sensor to have a resistance of around 10k Ohms for a temperature of -20C.

Then I put the multimeter on the sensor and got 430 Ohms:


With that result, I assume the sensor is broken. What puzzles me are the 2 following things:
1- No fault codes stored in the ECU
2- The gauge seemed to read correctly: it took a few minutes for the temperature to go up and then it stayed at 3 o'clock or slightly above.

I used a bluetooth OBD2 reader connected to my phone to read the codes. Maybe it's not really accurate and doesn't give all the codes.
For the gauge, the Volvo seems to have a narrowband gauge. It doesn't move from 3 o'clock even if you sit in traffic for long. For sure the coolant gets hotter during that time though. For reference, I also have a 190E, this has a wideband gauge that is graduated and the temperature fluctuates all the time depending if you're idling or driving and the outside temperature. I don't know how the gauge works in the Volvo, but it probably filters the signal from the sensor or something. Either that or my reasoning is not good or my test is bad. What do you think?

[Rocambolesque]

When doing the previous test, I didn't think to hook the OBD2 transmitter and see what kind of coolant temperature the ECU was seeing. I just did that and it was reading 68C, exactly in line with the 430 Ohm value I found. But then I noticed the temp gauge was at 4 o'clock and when I removed the key, the fan ran for a little while. I don't know if this just started happening or I didn't notice it before... I checked the sensor and it was connected properly, but the connector seems broken on the sensor side and the pins look offset. Sensor connected or disconnected, the coolant read 68C.

[scot850]

The thermostst opens at 90C so either the thermostat is not open or something is off. Was the engine up to temperature or was it at ambient temp when you did the test?

Neil.

[abscate]

I just remembered the table above has an error, if you look you can see how the numbers are not tBulated correctly , they are offset one column to the left

[Rocambolesque]

Engine was at ambient temp since it won't start!

I know about the table, I put the numbers correctly in the graph.

Also, since I last posted I re-did the test. Seems one pin was off in the sensor. I put it back and re-checked everything. Coolant temp read 51C and the gauge was at the bottom. The gauge probably starts moving around 60C.

I ordered a new sensor and a thermostat housing gasket. Along with that I received the ETM sensor today. Next weekend that thing will most likely start.

[Rocambolesque]

Update: the car is fixed.

I changed the coolant temp sensor. While I was in there, I also removed the throttle body and installed the sacer sensor in there. New plugs were also installed. The car started first try after that.

Today it was -25C again and the car started this morning like it was 20C. Thanks to everyone who helped.

[scot850]

Really happy to hear you got there in the end! That was a tough one and you got through it. Still think the temp sensor was the main culprit, but the Sacer kit is a great improvement (I have a Xemodex contactless ECM the PO installed, about the only good thing he did!), so that will have helped too.

Neil.

[abscate]

Argh!! Now we will never know which one it was!

Glad you got it running!