3.0 Duramax P1488 CEL code

Roomadder · September 24, 2020

This problem also seems to affect the Silverado 4500-6500HDs. My 2019 4500HD is currently in the shop for the 4th time for the P1488 code. It has already had the particulate filter and soot sensors replaced and new software downloaded but the problem still persists. I make a living out of this truck so it really hurts me when it is out of service. I hope GM figures out the problem soon.

PRNevada · October 8, 2020

Hello; New to the forum and found this thread when researching the P1488 code. Bought the truck in Reno NV in May 2020. Have not driven it much - now 3950 miles, mostly from long trips. CEL came on September 27. Took it to the dealer Oct. 7, and dealer found code P1488 and said that GM tells them to do a smoke test using tool GE-52250 (which the dealer does not have because GM has back ordered the tool for over a year). The dealer then told me that the GM suggested fix is to replace the particulate sensor - which is out of stock and back ordered. GM also asked the dealer to check that the sensor and the exhaust clamp are tight. Mechanic found both to be tight. Hopefully this is not the start of a long chain of problems as listed in other posts on this topic.

Pinnacle · October 9, 2020

8 hours ago, PRNevada said:

Hello; New to the forum and found this thread when researching the P1488 code. Bought the truck in Reno NV in May 2020. Have not driven it much - now 3950 miles, mostly from long trips. CEL came on September 27. Took it to the dealer Oct. 7, and dealer found code P1488 and said that GM tells them to do a smoke test using tool GE-52250 (which the dealer does not have because GM has back ordered the tool for over a year). The dealer then told me that the GM suggested fix is to replace the particulate sensor - which is out of stock and back ordered. GM also asked the dealer to check that the sensor and the exhaust clamp are tight. Mechanic found both to be tight. Hopefully this is not the start of a long chain of problems as listed in other posts on this topic.

So the tool and the part are backorder lol how bad is this? How long you gonna drive with that cel?

PRNevada · October 9, 2020

Hi; Dealer cleared the CEL, I drove the truck 20 miles home and it did not come back on. We will see how long it takes to re-light. I don't notice any change in how the truck drives, and the dealer did not raise any concerns about continuing to drive the truck while the issue remains unresolved.

10/16/20 Update: New Particulate Matter Sensor installed yesterday. The problem is explained in GM Tech-Link if you search PIP5748A. Hopefully the problem is resolved.

Edited October 16, 2020 by PRNevada
Updated Information

Steve-2019 · October 9, 2020

On 9/6/2020 at 9:00 AM, RockyBlue said:

Yes that is the one. I will be taking my truck to them next week to start the process. 30 days in the shop for them to try and fix. Then start the buy back process.

So did they get it fixed or are you in the buy back process now?

Serg76 · November 12, 2020

Any one has update on this topic i just got my truck 3 weeks about 1000 miles got code p1488 I took truck back to dealer 800 miles later got same code my truck been on dealer for 1 week this sucks

TheVez · November 13, 2020

On 10/9/2020 at 9:38 AM, PRNevada said:

Hi; Dealer cleared the CEL, I drove the truck 20 miles home and it did not come back on. We will see how long it takes to re-light. I don't notice any change in how the truck drives, and the dealer did not raise any concerns about continuing to drive the truck while the issue remains unresolved.

10/16/20 Update: New Particulate Matter Sensor installed yesterday. The problem is explained in GM Tech-Link if you search PIP5748A. Hopefully the problem is resolved.

So any luck? I read this last night and got the code today. Read this, came out only 3 days before you updated. https://gm-techlink.com/?p=13781 Taking it in in the morning. It’s awesome how duct tape is mentioned. Jesus GM.

edit to add: I just reread and the duct tape seems to be used to seal while using the sniffer for testing.

Edited November 13, 2020 by TheVez

TheVez · November 13, 2020

An update to the above. Dropped it at the dealer at 8am. New particulate sensor installed. First Oil change and picked up at 11:30am. I was prepared for a horrible experience but so far so good.

yousaveone · November 14, 2020

People need to quit relating the other Duramax to ours. Their not even ALMOST the same. the big diesels are designed by Isuzu and the babies by FEV. While the codes are the same in some instances this does not cross over from big engines to ours. You have a warranty and you bought a great engine with an ok truck wrapped around it. I have 36K on mine now and it just runs better every day. I think break in is close to done, my oil analysis levels look great.

KMK · November 14, 2020

My truck was in at 4999 km, for the same problem. Said original particulate sensor wasn’t torqued from the factory. 750 km later, same code. Appt next Friday again. Pissing me off is all. I’m a passive guy, but nearly $70,000 on a new truck? I’ll loose my ****** on them if this isn’t fixed this time!

Pinnacle · November 15, 2020

20 hours ago, KMK said:

My truck was in at 4999 km, for the same problem. Said original particulate sensor wasn’t torqued from the factory. 750 km later, same code. Appt next Friday again. Pissing me off is all. I’m a passive guy, but nearly $70,000 on a new truck? I’ll loose my ****** on them if this isn’t fixed this time!

Edited November 15, 2020 by Pinnacle

nickchodge · December 10, 2020

Same exact issue. Bought my Sierra AT4 in May. It has already been in the shop more than 30 days for this issue. Same thing with part not being available. Ultimately, the replaced the entire catalytic converter after going back and forth with Detroit. I requested replacement of the truck, but GMC would not do it on the same loan terms I have (0% interest). After reading this thread, I don't want a replacement now anyway. I am pursuing Lemon Law in Washington state and will request a buyback of the truck. GMC Customer Care and the dealership (George Gee, Spokane) were no help at all. Really a shame for the price.

Monte King · October 10, 2022

I have a 2021 High Country, 3.0l turbo diesel. At about 1000 miles, I got the dreaded CEL with a P1488 code. My dealer when thru all the required attempts to fix it; torque the particulate sensor, torque exhaust pipe clamp, add 'Tiger Tape' to the exhaust pipe joint, smoke test for exhaust leaks, replace the flex joint.....all to no avail. I was always skeptical about the exhaust leak theory. After all, how could the truck know there was a small exhaust leak to atmosphere?? In total, my truck was at the dealer service 7 times with no resolution. Each time they reset the code and the CEL always came back on within several hundred miles. I was finally able to get the regional service tech representative involved. He instructed my dealer to replace the whole exhaust system, including the cat convertor. Probably $2-3000 in parts. That has solved the problem.

Apparently there were some manufacturing variances with the exhaust pipe joint aft of the particulate sensor. This allowed a small air leak 'INTO' the pipe between exhaust pulses which confused the emission controls. A small number of exhaust pipes with this slightly defective joint all showed up with this same problem. I also had a particulate sensor that was occasionally sending bad data. This was identified using a data collector on a 10 mile drive.

I've since discussed this issue with an engineer friend who specializes in engine emission certification. He says the very first thing they do in preparing for a test run is pressure test the exhaust system and repair even the smallest leak. Otherwise, they would never get a consistent result. So, this rather implausible solution has some basis in science.

I've put about 10k miles on it since the fix and no CEL. Yea! I commend my dealer for sticking with me on this. They were carefully following the various Tech Bulletins and instructions from Detroit and always accommodated my schedule and provided a loaner car when there weren't many available at the time.

ElevatedBabyDiesel21 · October 10, 2022

Does anyone know if this was ever an official recall..or do all us 3L owners just have to wait, cross our fingers and hope we didn't receive one of the faulty exhaust systems? I just bought a '21 with 23K miles on it. Do they at least have a protocol in place now that allows for an expedient fix or do we have to go through all the B.S. multiple steps and then fight for a new exhaust setup?

Monte King · October 11, 2022

On 10/10/2022 at 2:45 PM, ElevatedBabyDiesel21 said:

Does anyone know if this was ever an official recall..or do all us 3L owners just have to wait, cross our fingers and hope we didn't receive one of the faulty exhaust systems? I just bought a '21 with 23K miles on it. Do they at least have a protocol in place now that allows for an expedient fix or do we have to go through all the B.S. multiple steps and then fight for a new exhaust setup?

I think this problem shows up early in the truck's life or not at all. Hopefully, you'll be ok.