Savtower Posted October 3, 2021 Report Share Posted October 3, 2021 Maybe you can help me before going to dealer. Story follows. Thanks in advance. 2009 Cadillac CTS purchase new 78000 miles. Problem started after driving and idling all day. Sitting at idle noticed temp gauge started climbing quickly to 280 with hot warning light on. Immediately stopped and turned car off. Opened hood and car didn’t seem that hot and with no apparent leaks. Vehicle returned to normal temp in approximately 30 minutes. Started up and car ran at normal temp (210) with no apparent problems. I have had a warning light on most of the life of car. Took to dealer several times and they reset it. I recently purchased an OBD II to check code. Received a code of p013a indicating lean bank 1 sensor 2. Reset code and just started having A/C problems. No code returned and engine running normal temp. AC seems to be partially working when driving but no AC at idle. Have dealer appointment coming up but hoping you could help me as the dealer I purchased car from reluctantly agreed to look at it but said they do not usually work on vehicles more than 10 years old. Quote Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted October 3, 2021 Report Share Posted October 3, 2021 based on your description one or both of the engine cooling fan(s) are not coming on. Quote Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
Logan Posted October 4, 2021 Report Share Posted October 4, 2021 That code kind of points to a sluggish O2 sensor. "DTC P013A: HO2S Slow Response Rich to Lean Bank 1 Sensor 2" I don't think it's related to the hot condition. Quote Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted October 4, 2021 Report Share Posted October 4, 2021 For diagnosing the cooling fans, generally there are two. The classic test is if it overheats while sitting still but not while moving, suspect the fans since they are what keeps air moving sitting still. You may be able to carefully, observe the cooling fans by looking down to the back of the radiator under the hood. This video discusses cooling fans However, don't replace ANY parts until you diagnose what is wrong. First (carefully) with the engine running and A/C on, observe if the cooling fan is running. Quote Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
Savtower Posted October 4, 2021 Author Report Share Posted October 4, 2021 excellent suggestion. I watched video and it exactly described my symptoms. I think i will take a shot at replacing fan motor. Thanks for the help. That video and the symptoms described was exactly what happened to me. Quote Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted October 4, 2021 Report Share Posted October 4, 2021 IF the fans are not operating, it needs further diagnosis. The fan motor may be faulty, may not be getting power (relay, fuse, or connection issue) or may not be commanded on (thermostat or relay issue). I try not to replace any parts until I know which one needs replacement. Quote Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
Savtower Posted October 4, 2021 Author Report Share Posted October 4, 2021 Great advice. I am not good at electrical testing. I will look at fuses and replace relays before replacement of fan motor. If that doesn’t work I will replace motor next if still nothing I will replace the connector to fan motor. If all that does not fix it it’s off to dealer and if I were younger maybe some electrical courses. I really appreciate you and others providing great advice. Quote Link to comment Share on other sites More sharing options...
Savtower Posted October 10, 2021 Author Report Share Posted October 10, 2021 Thank you Bruce, after heeding your advice and looking at the excellent videoI was able to pinpoint problem to fan. Further research I found a step by step procedure on replacement. Using the resources I was able to replace fan (one very hard hidden bolt to remove/replace) and everything now normal. Was able to cancel dealer appointment. Quote Link to comment Share on other sites More sharing options...
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