View Full Version : Need help with a used 2004 Cadillac CTS 3.6l ECU
Anyone out there with a scanner that can help me find out why my new car is having issues. I can't get it to pass the internal smog test to get it ready for Emissions test.
I was hoping someone has access to advance scanner like a Tech 2 or similar that can help me find out if the computer is bad.
The car's temp and gas gauge don't work. The gear shifter light doesn't light up and the reverse lights don't work either. I think they are all related to the ECU since I reset it and all those things worked for a little while. I was hoping to get it reflashed if it was done wrong the last time. The former owner changed the ECU and I'm not sure it was done right.
Thanks in advance. Of course I will pay. I'm just hoping to avoid the dealership fees for a car of this age. And I want to get someone that cares a little more than a run of the mill garage that will take your money but might not earn it.
Great-Kazoo
03-29-2019, 19:31
What does the smog place says is the reason you failed?
Anyone out there with a scanner that can help me find out why my new car is having issues. I can't get it to pass the internal smog test to get it ready for Emissions test.
I was hoping someone has access to advance scanner like a Tech 2 or similar that can help me find out if the computer is bad.
The car's temp and gas gauge don't work. The gear shifter light doesn't light up and the reverse lights don't work either. I think they are all related to the ECU since I reset it and all those things worked for a little while. I was hoping to get it reflashed if it was done wrong the last time. The former owner changed the ECU and I'm not sure it was done right.
Thanks in advance. Of course I will pay. I'm just hoping to avoid the dealership fees for a car of this age. And I want to get someone that cares a little more than a run of the mill garage that will take your money but might not earn it.
What does the smog place says is the reason you failed?
they can fail based on emissions related OBD systems not being online or not having run their internal diagnostics
SouthPaw
03-29-2019, 22:10
Did you just recently buy this car?
ChickNorris
03-29-2019, 22:49
Not necessarily helpful to your query but by Colorado law, a new emissions test is required prior to the sale on vehicles over 7 years for private transaction even if the vehicle has a current tag. Dealers may provide vouchers if a test isn't requested at point of sale.
matttahoe53
03-30-2019, 06:28
Has your battery died recently or been disconnected for a long time? If that is the case you will need to drive the car some distance so all the emissions equipment has had a chance to cycle a couple times, then the scan tool will then be able to retrieve the data on the equipment.
Great-Kazoo
03-30-2019, 08:29
they can fail based on emissions related OBD systems not being online or not having run their internal diagnostics
Right. However until one knows why it failed, guessing is just that. Did it fail for something simple, or will the new car repairs cost more than the OP wants to invest.
What does the smog place says is the reason you failed?
They said the onboard smog test stuff hasn't passed the tests yet. The cat, evap, O2 and O2 heater tests had not run yet and they kicked it out without further tests. I think I can have one not run yet. But I had 3 not run. There might be more issues going on to get it back to stock.
The brake lights were out and it was a bad soldier joint and that fixed it when I re soldiered the joints in a computer. A common problem with GMs.
Did you just recently buy this car?
Yeah. A month ago. I got it from my neighbor that had to get rid of it. His wife told him its cursed and needs to get rid of it. They are moving too and have to unload some of their stuff.
Has your battery died recently or been disconnected for a long time? If that is the case you will need to drive the car some distance so all the emissions equipment has had a chance to cycle a couple times, then the scan tool will then be able to retrieve the data on the equipment.It has sat for a year and the battery was changed before I got it. I recently put in a good battery that I know was new. Optima Redtop 1000 ca 800 cca.
I think that is what I needed. I hate throwing parts at stuff though without knowing that is what is wrong. But some of the gauges are not working and even though the emissions stuff still works. The evap test won't run, because it has to see the gas tank between 1/4 and 3/4 full and it doesn't show anything. The temp gauge doesn't show anything either. I think they are run by the ECU so its not sending any info to the gauges.
The emissions test looked for the internal smog test to run and the catalyst test, evap, O2 sensor and O2 heater test need to run and those take time. During the last month I have gotten all to pass except the EVAP test to run. I think I can run the emissions test with one not run yet. Now the temp tag is expired. I ordered another one over the phone and it was a 10 day tag. It started the day I ordered it and it showed up on day 8. SMH.
I think I need it reflashed with a stock program. I have seen mechanics updating the firmware like they were updating their phone or something.
Great-Kazoo
03-30-2019, 09:21
They said the onboard smog test stuff hasn't passed the tests yet. The cat, evap, O2 and O2 heater tests had not run yet and they kicked it out without further tests. I think I can have one not run yet. But I had 3 not run. There might be more issues going on to get it back to stock.
The brake lights were out and it was a bad soldier joint and that fixed it when I re soldiered the joints in a computer. A common problem with GMs.
Yeah. A month ago. I got it from my neighbor that had to get rid of it. His wife told him its cursed and needs to get rid of it. They are moving too and have to unload some of their stuff.
It has sat for a year and the battery was changed before I got it. I recently put in a good battery that I know was new. Optima Redtop 1000 ca 800 cca.
I think that is what I needed. I hate throwing parts at stuff though without knowing that is what is wrong. But some of the gauges are not working and even though the emissions stuff still works. The evap test won't run, because it has to see the gas tank between 1/4 and 3/4 full and it doesn't show anything. The temp gauge doesn't show anything either. I think they are run by the ECU so its not sending any info to the gauges.
The emissions test looked for the internal smog test to run and the catalyst test, evap, O2 sensor and O2 heater test need to run and those take time. During the last month I have gotten all to pass except the EVAP test to run. I think I can run the emissions test with one not run yet. Now the temp tag is expired. I ordered another one over the phone and it was a 10 day tag. It started the day I ordered it and it showed up on day 8. SMH.
I think I need it reflashed with a stock program. I have seen mechanics updating the firmware like they were updating their phone or something.
Don't forget to put a new gas cap on before the test. It's the weakest link and most overlooked in the system.
BushMasterBoy
03-30-2019, 10:16
I have an Optima Red top that lasted two years. It is still sitting on the kitchen floor. It was a problem with my 07 Silverado radio drawing it down. Dealer had to reprogram a "body control module/ radio".
My suggestion is charge the battery fully. Check the voltage, should be above 13 volts fully charged. You will need a cheap digital multimeter for this. The Optima battery manufacturer has had serious quality control declines according to some truck forum members.
Another suggestion is to get a Blue Driver OBD reader that Bluetooth connects to your smart phone. The app is a free download. The Blue Driver is a $100 new on ebay. I have seen used go for $80. An OBD reader is indispensable these days and will pay for itself in short time. There are other OBD readers that are cheaper. I hope this information helps.
https://www.bluedriver.com/
Or a cheaper version...
https://www.amazon.com/Vgate-Bluetooth-Scanner-Adapter-Diagnostic/dp/B019SURWYO
sportbikeco
03-30-2019, 10:58
OBDII scan tool is $20 at Walmart.
BTW check engine light won't automatically make you fail with that year of car of it passes the sniffer, but I didnt know they could fail you because the scan says its out of wack without running the test as well (never been in that scenario, but have had cars that throw numerous codes pass such as o2 sensor, knock code etc)
How fast do the codes come back after your clear them?
I also have a snap on solis that reads more than obd codes and can read and clear all codes from all modules and see if the obd sensors have run their trip cycles
if you need to borrow it
BushMasterBoy
03-30-2019, 12:59
Then there is this one on sale from Amazon
https://www.androidcentral.com/thrifter-deal-tacklife-obd-ii-bluetooth-auto-code-scanner-diagnostic-tool
Some Buicks and Cadillacs have there own onboard scanner. You might check online for information.
My 94 Buick scanner reads out of the dash HVAC display unit.
Or spend $100.00 and buy your own scanner that reads through your smart phone via bluetooth. We are happy with Blue Driver scanner. Reads, translates and clears codes.
I also have a snap on solis that reads more than obd codes and can read and clear all codes from all modules and see if the obd sensors have run their trip cycles
if you need to borrow it
That is what I was hoping for. I did buy the Blue Driver and its cool. But it doesn't test mods. It just monitors them. Can I PM you to get the info on it?
Walker2970
03-30-2019, 21:38
Cadillac's are easy to fix..... light a flare, drop in gas tank,RUN issues fixed
BushMasterBoy
03-31-2019, 20:41
https://www.youtube.com/watch?v=9rWnCCAycjs
Great-Kazoo
03-31-2019, 21:42
Cadillac's are easy to fix..... light a flare, drop in gas tank,RUN issues fixed
Jewish lightening can strike anytime, anywhere.
2004 is old enough that they should run it even if it doesn't communicate at all, unless denver is extra screwy. I see badly trained emissions people all the time. I work at a emissions certified shop in northern colorado. You need to find out which testing station has employees that know what they are talking about. There is also a consult guy up here, find out where down therehe works or phone number and see him.
Powered by vBulletin® Version 4.2.3 Copyright © 2025 vBulletin Solutions, Inc. All rights reserved.