Well this one caught me off guard...especially since I need the car running for my scheduled tune on Friday.

I'm experiencing B2722 (H & C) PASS-Key Detection Circuit and I'm hoping someone can help me troubleshoot. Last week, I had my PCM reflashed to 2-bar OS; however, I started the car multiple times after that without a hitch.

Symptoms: Key to 'On' and everything functions properly. Everything lights up and fuel pump primes. Key to 'Start' and NOTHING, no click, NOTHING. The gauges go dark but that's the only thing that happens.

The B2722 H C is the only code that will not clear via the DIC.

Can someone please help me troubleshoot this? I've been searching on here, but unfortunately the only hits I'm getting are the entire DIC code listings that people re-post over and over and over.

Thanks,
Matt

 

Going to try this, but input still appreciated.

http://www.hptuners.com/forum/showpo...72&postcount=5

 

No success.

 

DTC B2722
Circuit Description
The body control module (BCM) supplies a 5 volt signal and a ground circuit for the PASS-Key® system. This allows the BCM to detect PASS-Key® resistance values. Inserting the PASS-Key® (with resistor pellet) in the ignition lock cylinder completes the PASS-Key® circuit. Contacts in the ignition lock cylinder mate with the pellet contacts. The BCM compares the resistance value of the key pellet to the valid resistance programmed into the BCM. If the proper resistance value is read, the BCM allows the following functions to occur:

• The theft deterrent relay to energize.

• The steering column to unlock.

• The BCM sends a message through the serial data line to the powertrain control module (PCM) to allow fuel delivery to occur.

If the resistance value is incorrect, a malfunction is present and a DTC will set.

Conditions for Setting the DTC
• The voltage level sampled at the BCMs PASS-Key® signal circuit is incorrect, signaling that an invalid PASS-Key® resistance was detected, and a short is present.

• This condition must be present for 1 second.

Action Taken When the DTC Sets
• The BCM stores DTC B2722 in memory.

• The BCM sends a message to the instrument cluster to illuminate the SECURITY indicator.

• The BCM disables the theft deterrent relay.

• The PCM will not allow fuel delivery to occur.

• The BCM disables sampling of the PASS-Key® resistance for a time-out period of 3 minutes.

• The steering column remains in the locked position.

Conditions for Clearing the DTC
• This DTC requires an ignition cycle in order to change from current to history.

• The BCM detects a valid PASS-Key® resistance value on the PASS-Key® signal circuit.

• A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.

• Use the instrument panel luster (IPC) clearing DTCs feature.

• Use a scan tool.

Diagnostic Aids
• If the key resistor pellet is incorrect, there will be no BCM outputs to the theft deterrent relay or to the PCM. This state will last about 3 minutes. If a key is inserted, or the ignition is turned ON again before the 3 minute time frame is complete, the timer will reset to 3 minutes. Disconnecting the battery will not clear the timer sequence, but the timer will reset to 3 minutes when the battery power is restored. Even if a proper key is inserted during one of the time periods, the vehicle will not start until the total time period has elapsed.

• If there is a short between the PASS-Key® signal and ground circuit, or a short to ground on the PASS-Key® signal circuit, the vehicle will exhibit a no crank condition.

Test Description
The number below refers to the step number on the diagnostic table.

This test verifies the integrity of the key resistor circuits between the ignition switch and the BCM.

Step
Action
Yes
No

Schematic Reference: Theft Deterrent System Schematics

Connector End View Reference: Theft Deterrent System Connector End Views

1
Did you perform the Theft Deterrent Diagnostic System Check?
Go to Step 2
Go to Diagnostic System Check - Theft Deterrent

2
Install a scan tool.
Turn ON the ignition with the ignition OFF.
Select the BCM Display DTCs function on the scan tool.
Does the scan tool display B2722 as a current DTC?
Go to Step 3
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3
Inspect the ignition key for dirt or obvious damage.

Does the ignition key appear dirty or damaged?
Go to Step 8
Go to Step 4

4
Turn OFF the ignition.
Disconnect the ignition lock cylinder connector.
Connect a J 35628-A Vats/Passkey Interrogator using terminal adapters from a J 35616 to the key resistor input circuit and key resistor reference ground circuit.
Insert the ignition key into the key code reader on the J 35628-A and note the code on the LCD display.
Turn the rotary switch on the J 35628-A to the same code number as the ignition key.
Attempt to start the vehicle.
Does the vehicle start?
Go to Step 7
Go to Step 5

5
Test the key resistor input circuit for a short to ground.

Did you find and correct the condition?
Go to Step 11
Go to Step 6

6
Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 11
Go to Step 10

7
Inspect for poor connections at the harness connector of the ignition lock cylinder. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
Go to Step 11
Go to Step 9

8
Clean or replace the ignition key as necessary. Refer to Replacing Keys .

Did you complete the procedure?
Go to Step 11
--

9
Replace the ignition switch lock cylinder. Refer to Ignition Switch Lock Cylinder Replacement in Instrument Panel, Gages and Console.

Did you complete the replacement?
Go to Step 11
--

10
Important: When replacing the BCM, perform the relearn procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the repair?
Go to Step 11
--

11
Use the scan tool in order to clear the DTCs.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?
Go to Step 2
System OK

 

Thanks for that process, going to read over it more thoroughly again.

One oddity that contradicts the above symptoms is that my Security light is solid under this condition and my column does not lock (I'm assuming this is contributed to my CLB).

 

I'm thinking this is more along the lines of scenario #1. Not sure if it's related, but I'm going to have a friend disable VATS via HP Tuners. If that doesn't work, at least that's one thing to check off the list.

 

Can HPTuners reprogram the BCM? I thought it was limited to the PCM. If you can't reprogram the BCM it will still keep the engine from starting. Spray some electrical contact cleaner into the ignition lock cylinder and the pill on the key. The code is telling you that the key isn't being read correctly. As far as I know HPTuners is a great tool for playing around with the PCM but falls on its face once outside that area.

Bill

 

You're probably right about HP Tuners...I don't know enough about it to say either way.

I'm hoping the spray works, ugh what a PITA. Always happens at the worst times.

 

HPTuners CAN NOT reprogram the BCM.

 

Time to get the garden shears out, delete anything that looks like a wiring harness in the car, and set a nice big carb on top of the motor. Maybe even convert to pull start.

 

Well I did the relearn and didn't have any immediate success. Then I jiggled the key around in the 'Start' position and the car fired and ran. After turning the car off, I tried to start it again with no success. I think the key has too much play in it and is not completing the Pass Key circuit. Should I be looking to replace the ignition at this point?

 

I would troubleshoot, and isolate the issue. Do you have a service manual? Can you read schematics? Do you have a meter?

 

I will have a service manual very shortly. Regrettably I can only read the most basic of schematics; however, I do have a meter.

Having never disassembled the ignition cylinder, I do not know exactly how it functions. I'm assuming both pellets on the key need to contact fingers to complete the circuit? The key has a lot of lateral movement.

 

YEP, sounds like a new ingition switch or a bypass resistor soldered in.

 

If it's of any help to you I had the same issues not too very long ago. I did a bypass with a resistor soldered in. Started right up.

 

I can send you the procedures. Be careful who you listen to, because the whole ignition switch is not required.....rather.(if troubleshooting leads to it).....just the lock cylinder.

 

Good to know. The more research I do, the more I find this to be a fix for my symptoms.

 

Thank you. I will PM you my email address.

 

Email sent.

 

Just to follow up, I jumpered the VATS circuit with the appropriate amount of resistance and the car fired right up.