P2138 '59 Apache
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Teching In
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P2138 '59 Apache 
Hey guys. I'm relatively new here and looking for some advice.
Here is my journey:
Mine is a 1959 Chevy Apache long bed, mounted on a 1979 K20 4x4 frame. Its sports an LS3 430 Hp, 430 FT/lbs connect and cruise from Chevy performance. It has a 4l70e transmission. 4.10 gears in both axles.
Some notables: Dakota Digital cluster, vintage air a/c..... DD cruise
The truck has about 55,000 miles on it since the swap.
The first 35,000 miles were amazing and trouble free
Then the drama began.
What I've tried since the P2138 code started:
replaced Throttle body, ECU, pedal , Changed both wire pigtail ends, DD cruise to pedal harness.
Like others, there is no rhyme or reason. I have driven a few thousand miles without and issue, and other times I can't go 1/10th of a mile.
For the longest time, I thought that it was the DD cruise control. I drove without the pedal harness attached and thought I'd solved the issue.
When it started again, I completely removed the cruise....wiring, box and all.
Again, because I drove a couple of thousand miles without the code, I thought it was fixed.
nope
So lastly I attempted to replace the pedal pigtail again. It seemed that every time that I unplugged and plugged it back in, I experienced some success.
But, now the truck immediately throws the code and it won't reset
So what would yall do?
1) replace the TB, pedal , and harness as a group? about $1500 in parts
2) do the conversion from a drive by wire to a cable driven setup? not sure the cost
3) other
thanks in advance
Teching In
Joined: Jul 2021
Posts: 27
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Is this a factory ECU? Not familiar with connect and cruise but a quick search looks like it’s a factory powertrain kit. If that’s the case HP tuners may aide in troubleshooting your issue. I wouldn’t recommend getting it just to troubleshoot (or for anything else really), it is becoming somewhat of a relic with systems like Holley on the market, but for diagnosing issues it can be a powerful tool. You can log just about every signal going to and from the ecu, which I’m guessing something isn’t quite going through based on the connector giving inconsistent results.
Id ask around your area if anyone has it. If you were local to me I’d gladly lend a hand - Bay Area, Northern California.
Id ask around your area if anyone has it. If you were local to me I’d gladly lend a hand - Bay Area, Northern California.
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Teching In
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The last program tuner that I had look at it, said that Chevy performance has locked the ecu.
Our thought was to change the voltage parameters so that the code wouldn't be thrown anymore. Or, eliminate the P2138 limp mode completely.
From my understanding, it's a bad connector, pedal, ecu , TB or a bad ground somewhere. I think someone on here suggested a ground to the OBDII port
IDK....
Our thought was to change the voltage parameters so that the code wouldn't be thrown anymore. Or, eliminate the P2138 limp mode completely.
From my understanding, it's a bad connector, pedal, ecu , TB or a bad ground somewhere. I think someone on here suggested a ground to the OBDII port
IDK....
Teching In
Joined: Jul 2021
Posts: 27
Likes: 22
I would imagine parameters could be read even with the ecu locked, but I’m not sure what sort of evil they can muster. Last time I had to deal with limp mode it was a constant 12v thing, so I’d maybe poke around for a blown fuse if you haven’t already. However, in my case the trans did not have constant 12v to the plug.
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Teching In
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I decided to replace the drive by wire throttle system. I pulled out the old wiring and noticed a few slices.
1) a splice into the #2 cylinder harness (fuel I'm guessing)
2) A Dakota Digital module box wire spliced into the OBD2 harness
3) A pigtail labeled rev limit spliced into the OBD2 harness (not attached anywhere)
4) A couple of the connectors that went to relays had some exposed wires.
5) The throttle body had some grime inside it
A) The #2 cylinder confused me. I'm guessing maybe part of my alarm system? IDK
B) I've called DD, their old setup was a connector that plugged into the OBD2 port. I'm guessing that my installer cut that and did the splice. DD is sending me the correct harness. The down side to that is, my Fixed blue-tooth plug can't live in the port anymore. That's how I would get the truck moving again in a hurry. But, hopefully I won't have that issue anymore.
C) I won't be using the rev limit
D) I replaced the wire connectors and either shrink wrapped or taped the ends
E) TB has been replaced. I will clean the old one and have a spare
All of the grounds were good and solid, so I'm guessing that my issue rested in all of the splices.
The new harness won't be routed as cleanly and professionally as the original was, but hopefully my issue will be resolved.
I will know by the end of the weekend.
I completely removed the DD cruise control and won't reinstall it. It will be missed....
1) a splice into the #2 cylinder harness (fuel I'm guessing)
2) A Dakota Digital module box wire spliced into the OBD2 harness
3) A pigtail labeled rev limit spliced into the OBD2 harness (not attached anywhere)
4) A couple of the connectors that went to relays had some exposed wires.
5) The throttle body had some grime inside it
A) The #2 cylinder confused me. I'm guessing maybe part of my alarm system? IDK
B) I've called DD, their old setup was a connector that plugged into the OBD2 port. I'm guessing that my installer cut that and did the splice. DD is sending me the correct harness. The down side to that is, my Fixed blue-tooth plug can't live in the port anymore. That's how I would get the truck moving again in a hurry. But, hopefully I won't have that issue anymore.
C) I won't be using the rev limit
D) I replaced the wire connectors and either shrink wrapped or taped the ends
E) TB has been replaced. I will clean the old one and have a spare
All of the grounds were good and solid, so I'm guessing that my issue rested in all of the splices.
The new harness won't be routed as cleanly and professionally as the original was, but hopefully my issue will be resolved.
I will know by the end of the weekend.
I completely removed the DD cruise control and won't reinstall it. It will be missed....
Thread Starter
Teching In
Joined: Sep 2022
Posts: 5
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update
The splice in the #2 injector harness was for the remote start. It reads a positive input to tell the starter when to stop spinning. I will probably reconnect that
The new hardware has been great. No issues so far.
Leads me to believe that my 3 year battle with this was because of the DD harness being spliced into the OBD2 port section of the harness.
I am not splicing the new harness. Instead, the DD will remain plugged into the OBD2 port
The splice in the #2 injector harness was for the remote start. It reads a positive input to tell the starter when to stop spinning. I will probably reconnect that
The new hardware has been great. No issues so far.
Leads me to believe that my 3 year battle with this was because of the DD harness being spliced into the OBD2 port section of the harness.
I am not splicing the new harness. Instead, the DD will remain plugged into the OBD2 port
