Cadillac Seville / Cadillac Eldorado Forum Discussion, code P 0135 - 2002 Eldorado in Past Cadillac Vehicle Discussion; Have 2002 Eldorado, #1496
Code po135 is present, 02sensor Heater Circuit Bank 1 sensor.
Car has always stayed at the ...
When does the temp gauge needle "move" - under what conditions of car operation: traffic, idling, road speed, HVAC On or OFF ?
The gauge needle should move a bit to the right when in heavy traffic or simply sitting still, idling, with no A/C function set.
Take a look at the annotated temp gauge in my albums for how and when fans and thermostats work. Click my username, open the profile. Left column, 2 albums, 6 pages of FWD Northstar stuff and parts for your engine.
It was great talking with you a couple of weeks ago, I had called and asked about the speed sensor, that was the first code that showed. I cleared the code and drove a little and now code 135 shows. Going to replace the 02 sensor on bank I. I have read other post inregards to replacing, but am not sure on how to tell if it is the one before the cat. or behind it?
I am not sure, but the temp. gauge rising to about 1 oclock could have been from using the HVAC, this is the first time I had used it. The temp. gauge would fall back to 12 oclock when moving on the open road.
Am new at posting, but plan on telling about my 2002 ETC on a later date.
I used the HVAC for the first time and will see if that could have caused the rise in temp. I also pulled up your annotated temp gauge, thanks. The caddy has never ran hot, with all the problems that others have had I keep a constant eye on that gauge.
Going to replace the 02 sensor, per reading previous posts bank one is on the left, farthest from the fire wall. How do you tell if it is the one before or after the Cat?
Again thanks for you input, I have been reading all the post for sometime now, but have never posted. Hope to post more about my Caddy later.
In the 2000 - 2004 Northstars there are 3 O2 sensors.
Left (front) bank exhaust manifold collector = B2S1 (plugs 2-4-6-8)
Right (rear) bank exhaust manifold top = B1S1 (plugs 1-3-5-7)
After-cat passenger side of pipe = B1S2
In the earlier models there is also a pre-cat sensor, so the right bank/exhaust numbering is B1S1, B1S2, B1S3.
If you really want to see what YOUR engine is doing in any 4 of 12 gauges at a time, take a look at a ScanGauge-II. The unit can also be programmed by you to show an additional 4 gauges, depending on just what your engine monitors (GM service manual info). The unit is also a code scanner and secondary fuel mileage computer. Two units may be daisy-chained and will display 8 gauges at one time. I use one and normally monitor intake air temp, coolant temp, ignition timing and MAP (inverse vacuum). www.scangauge.com
Your code is specifically for the heating circuit in the O2 sensor. Nothing else can cause the code.
Your temps are fine, and the fans are coming on when they should be (low speed ~224, high speed ~236). If you believe the engine is running hotter than it used to, check for dirt/leaves/debris buildup on the condenser, and check the condition of the water pump belt and tensioner.