20' Sierra Remote-Start not working

KinkyDuramax · December 11, 2023

Hi,

Both key fobs for my 20' Sierra is not working for remote-start. However it does unlock/lock/open tail gate Etc.

I've replaced both batteries in the fobs, and tried again no luck. Anything I'm missing here?

Previous to this problem: I had a CEL due to a TSB that was resolved the other day. The GMC Dealership instructed us to wait after the CEL clears to attempt a remote-start. A friend of mine (former mechanic at the same GM dealer) mentioned that an electronic hood latch could set the computer to not allow remote-start (odd I know). He mentioned I'd have to pop by and have him plug in the truck to the system and see whats causing it to not remote-start.

I'm still planning on doing so, but in the mean time has anyone else witnessed this problem? I've been researching but doesn't seem like much information, maybe just bugged out?

Some websites show like low coolant, or pressure but I've never seen an error on the dash Etc.

The truck just ticked over 60k. My 23' doesn't have this issue.

SteveP45 · December 11, 2023

Could be a defective hood latch…. Any other false MIL appearing? Like false service esc or service abs or service fwd without codes being generated and stored for the false MIL

will remote start work at least once after all codes are cleared?

Do you run your vehicle through high pressure car washes or use a pressure sprayer on the front anywhere near the hood latch

KinkyDuramax · December 11, 2023

9 minutes ago, SteveP45 said:

Could be a defective hood latch…. Any other false MIL appearing? Like false service esc or service abs or service fwd without codes being generated and stored for the false MIL

will remote start work at least once after all codes are cleared?

Do you run your vehicle through high pressure car washes or use a pressure sprayer on the front anywhere near the hood latch

No other codes are showing actively when driving, or starting up. The mechanic would have to plug in and check. I don't have a tool myself.

Prior to this, it did work yes.

The truck doesn't get washed often, but if it does it will go through a touchless or one of those that go on the belt.

ember1205 · December 11, 2023

First, get an ODB II tool. I bought one a couple of years ago when my 2015 threw a CEL and it has been invaluable since (just repaired an "Emissions" problem on the wife's car for cheap with the help of the reader).

Second - There are different types of codes. Predominantly, we talk about DTC's (Diagnostic Trouble Codes). When the ECU detects that something is not operating as expected, it will illuminate (or in some cases flash) the CEL to let us know something is amiss. These codes can be cleared but will return if the underlying problem is not corrected. Once cleared, the CEL will go away until the code gets set again.

Then there are PDTC's (Permanent DTC's) which are retained in the ECU even after the DTC that caused it has been corrected. Mostly, these are the result of things like evap / emissions related issues. This is what happened with my wife's car - I could clear the DTC but it remained in the ECU as a PDTC.

The way you clear a PDTC is to correct the underlying problem that cause the DTC, clear the DTC, then drive it for "a while." It will take some combination of drive cycles (warm up / cool down) and distance driven for the ECU to determine that the original DTC is not returning and then it will clear the PDTC out on its own.

There are also Pending Codes which are when the ECU detects something is off, but wants to see what happens over the next couple of drive cycles to decide if the code needs to be set and the CEL illuminated.

You could have a combination of DTC's, Pending Codes, and PDTC's in the ECU that are preventing the remote start from working. inCarDoc and Track Addict are two good apps for your phone that will work with a number of basic OBD II reader plugs. For reference, if you are interested, this is the one I have: https://a.co/d/3XwBOlw

For less than $25, I have a useful tool that allows me to look just a touch "deeper" into what's going on with my vehicles before I head down the path of bringing it to a mechanic. I was able to diagnose a failing high pressure fuel pump on my 2015 Silverado and a failed Oil Pressure Switch on my wife's Acura. While I leveraged a private mechanic for the truck, I supplied my own OEM parts at a significant discount compared to what he would have had to charge for them and I was able to fix the latter issue on my own in about 5 minutes with just the replacement switch (under $50).

redwngr · December 11, 2023

Any of these apply?

newdude · December 11, 2023

1 hour ago, ARedSierra said:

Hi,

Both key fobs for my 20' Sierra is not working for remote-start. However it does unlock/lock/open tail gate Etc.

I've replaced both batteries in the fobs, and tried again no luck. Anything I'm missing here?

Previous to this problem: I had a CEL due to a TSB that was resolved the other day. The GMC Dealership instructed us to wait after the CEL clears to attempt a remote-start. A friend of mine (former mechanic at the same GM dealer) mentioned that an electronic hood latch could set the computer to not allow remote-start (odd I know). He mentioned I'd have to pop by and have him plug in the truck to the system and see whats causing it to not remote-start.

I'm still planning on doing so, but in the mean time has anyone else witnessed this problem? I've been researching but doesn't seem like much information, maybe just bugged out?

Some websites show like low coolant, or pressure but I've never seen an error on the dash Etc.

The truck just ticked over 60k. My 23' doesn't have this issue.

CEL stops the remote start from working. Bad hood latch can too and often the failed latch will set the CEL.

Edited December 11, 2023 by newdude

SteveP45 · December 12, 2023

A faulty hood latch may not result in any codes being generated or stored. I posted extensively on this about a year ago. You may get false MILs and no codes generated or stored. Or the false MIL may store a code. Once the codes are cleared the remote start may work once or twice. It took several months to get to the real cause,. A faulty hood latch which was not generating the correct resistance, but it was also not causing a hood open MIL either.

Also make sure all the windows are fully up... if they are down just a hair, the remote start will not work, Also if a door is not fully closed it will not work, nor will it work if a sliding back window is not fully closed,,,, it will not work if the throttle pedal is depressed at all by anything.... it will not work if the fuel pressure is not correct......or if the battery is low....etc...

redwngr · December 12, 2023

1 hour ago, SteveP45 said:

A faulty hood latch may not result in any codes being generated or stored. I posted extensively on this about a year ago. You may get false MILs and no codes generated or stored. Or the false MIL may store a code. Once the codes are cleared the remote start may work once or twice. It took several months to get to the real cause,. A faulty hood latch which was not generating the correct resistance, but it was also not causing a hood open MIL either.

Also make sure all the windows are fully up... if they are down just a hair, the remote start will not work, Also if a door is not fully closed it will not work, nor will it work if a sliding back window is not fully closed,,,, it will not work if the throttle pedal is depressed at all by anything.... it will not work if the fuel pressure is not correct......or if the battery is low....etc...

Hood switch doesn't have to be faulty, just has to be open.

I've never heard / read about 'window open' stopping remote start.

Got something new to test now!

Edited December 12, 2023 by redwngr

ember1205 · December 12, 2023

6 hours ago, redwngr said:

Hood switch doesn't have to be faulty, just has to be open.

True, but I think what @SteveP45 is saying is that the latch could be faulty and ultimately be at least participating in the cause, and you wouldn't necessarily know because the issue isn't "bad enough" for the truck to throw any sort of code or light up the CEL. So, even with the hood closed, and the truck not seeing "hood open", the latch could still be the culprit.