Another 2011 Tahoe won’t crank

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
23,409
Reaction score
34,035
Location
Stockton, Ca.
if you replace that module then you will have to do a relearn, the instructions must be followed correctly.

Passkey III – transponder ignition key. The Passkey III anti-theft system uses a
transponder inside the head of the ignition key. The exciter inside the ignition lock
cylinder energizes this transponder when the ignition switch is turned on. The
transponder transmits a unique signature to the theft deterrent control module. If the
key signature transmitted is acceptable to the theft deterrent control module the theft
deterrent control module will transmit fuel enable password to the PCM. If the fuel
enable password is correct the PCM will start the vehicle.
To perform a relearn on a Passkey III system make sure there is a fully charged battery
in the vehicle. The battery will be used for 30 minutes without the alternator available
for charging. Connect a battery charger to the battery to ensure power is available while
programming. When performing this relearn all previously learned keys will be erased.
Additional keys may be relearned immediately after the first key has been learned by
inserting the additional key and turning the ignition switch to on within 10 seconds of
removing the previously learned key.
1. Insert a master key (black head) into the ignition switch.
2. Turn key to the “ON ” position without starting the engine. The security light should
turn on and stay on.
3. Wait for 10 minutes or until the security light turns off.
4. Turn key to the “OFF ” position for 5 seconds.
5. Turn key to the “ON ” position without starting the engine. Security light should turn
on and stay on.
6. Wait for 10 minutes or until the security light turns off.
7. Turn key to the “OFF ” position for 5 seconds.
8. Turn key to the “ON ” position without starting the engine The security light should
turn on and stay on.
9. Wait for 10 minutes or until the security light turns off.
10. Turn key to the “OFF ” position. The key transponder information will be learned on
the next start cycle.
11. Start the vehicle. If the vehicle starts and runs normally, the relearn is complete.
12. If additional keys need to be relearned, turn the key to the “OFF ” position.
13. Insert the next key to be learned. Turn the key to the “ON ” position within 10
seconds of removing the previously used key.
14. Wait for security light to turn off. It should happen fairly quickly. You may not notice
the lamp as the transponder value will be learned immediately.
15. Repeat steps 12 through 14 for any additional keys.
 
OP
OP
O

OLEJOE

TYF Newbie
Joined
Sep 8, 2019
Posts
21
Reaction score
5
I thought it was. The info I can find says it has to be programmed by the dealer but would the key relearn do it? Thanks
Guess I was typing while you were
 
OP
OP
O

OLEJOE

TYF Newbie
Joined
Sep 8, 2019
Posts
21
Reaction score
5
I’m still getting no communication message. Pin 6 on dtc is what the Tech II is saying but I have no idea what or where it is supposed to connect. Anyone have an idea?
 
OP
OP
O

OLEJOE

TYF Newbie
Joined
Sep 8, 2019
Posts
21
Reaction score
5
It’s not a power issue. Scanner will connect to everything but the ECM, BCM and TCM. I can pull up information on the theft Deterrent Module. Power pins are powering. I need a wiring diagram or need to know which pin on the ECM or BCM is supposed to connect to the diagnostic tool connector. Thanks


I cleaned the cable ends and the maxifuse. If the ECM isn’t getting power, it has to be between the fuse and the ECM in the wiring. The truck will crank intermittently but will only run 3-4 seconds.
 
Last edited:
OP
OP
O

OLEJOE

TYF Newbie
Joined
Sep 8, 2019
Posts
21
Reaction score
5
Well new problem. Now when it sits idle for 10 or 15 minutes all power shuts off and you have to turn the headlights on and it will resume. Anti theft light on and I’ve tried the key relearn 3 times with no success. I think it’s time for it to go to the dealer.
 

Forum statistics

Threads
128,790
Posts
1,805,497
Members
91,773
Latest member
wbhidalgo17
Top