2002 Chevrolet Impala

Electrical problem
2002 Chevy Impala 6 cyl Front Wheel Drive Automatic 100134 miles

I would like to know how to replace the igition switch on a 2002 Chevy Implala, it is in the dash, not the coloum and need to know the easiest way to get to it, test it and replace if need be.

Thanks Doc.
November 10, 2008.

Hope this is of use

NOTE:Door, trunk and ignition are operated by one key. If procedure requires ignition switch lock cylinder to be replaced, new ignition switch lock cylinder should be recoded to old key.

NOTE:Passlock(tm) sensor is an integral part of ignition switch assembly.

Disconnect negative battery cable. Remove access cover from left instrument panel fuse block. Release left instrument panel insulator tabs from lower instrument panel trim pad retainers for access. Remove bolts from steering column filler panel. Release steering column filler panel retainers from instrument panel lower trim panel. Carefully lower panel away from instrument panel lower trim panel. Disconnect electrical connector from rear compartment release switch. Remove rear compartment release switch. Remove steering column filler panel.
Remove bracket bolts from instrument panel driver knee bolster. Remove bracket bolts from instrument panel knee bolster at instrument carrier. Remove knee bolster bracket.
Remove instrument panel cluster trim plate. See INSTRUMENT PANEL CLUSTER TRIM PLATE . Remove ignition switch retaining bolts. See Fig. 19 . Lower ignition switch away from instrument carrier.
Insert key into ignition switch and turn to RUN position. If ignition switch lock cylinder rotates, go to step 8 . If ignition switch lock cylinder will not rotate or is seized, go to next step.
Protect immediate work area with clean shop towels or a clean fender cover. Locate surface for ignition switch lock cylinder release button (2) on plastic ignition switch housing and center punch a location (1) on rib approximately 3/8 inch toward key entry end from cylinder release button. See Fig. 20 .
Carefully drill a pilot hole through plastic housing with a 1/8 inch drill bit. Carefully drill a larger hole at pilot location, and slightly into ignition switch lock cylinder surface to break release button retaining spring using a 9/32 inch drill bit. Remove portions of broken spring from hole using a small suitable tool.
Grasp ignition switch lock cylinder and remove it from switch housing. Remove any plastic from drilling operation, and using compressed air blow out ignition switch assembly. Go to next step.
NOTE:The Passlock(tm) electrical connector cannot be removed until lock cylinder is removed.

Depress transaxle park/lock cable retainer to release. Pull to remove park/lock cable from ignition switch. Depress detent on bottom of ignition switch in order to release ignition lock cylinder. Remove ignition lock cylinder with key. Disconnect Passlock(tm) electrical connector. Disconnect electrical connectors.

Removal & Installation (Impala)
CAUTION:Use correct fastener in correct location. Replacement fasteners must be correct part number for application. Fasteners requiring replacement or fasteners requiring use of thread locking compound or sealant are identified in service procedures. DO NOT use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage fastener. Use correct tightening sequence and specifications when installing fasteners in order to avoid damage to part and systems.

Apply parking brake. Using a small flat-blade tool, remove bezel from ignition switch cylinder. If vehicle is equipped with a column shift, shift transaxle in to first gear. Ensure ignition key is in ignition lock cylinder.
Adjust steering wheel to gain access. Remove access covers from right and left instrument panel fuse block, as required. Remove screws from instrument cluster trim plate.
Starting at right end of instrument panel cluster, pull trim plate rearward. See Fig. 21 . Continue working around instrument cluster trim plate until all retainers are released from instrument trim pad. Disconnect electrical connector from hazard switch and from traction control switch (if equipped). Remove instrument panel cluster trim plate. To install, reverse removal procedure.

Dave H
Nov 10, 2008.
Well I got the switch out and replaced it and still the car does not start. All fuses check ok.

So now what do I check?

Nov 13, 2008.
I thought the ignition was broken in some way. From the way you asked in your first post? Can I ask what the car was doing to make you replace the ignition switch? An what it is doing now still of course?

Dave H
Nov 13, 2008.
You probably have a bad passlock sensor which is the part that plugs into the ignition switch.

Nov 13, 2008.

I am sorry that I did not state my problem first or along with my request.


Where would that be located, I just replaced the Ing switch. I seen the wires from the passcode plug, but I did not know where they go once they go into the wiring loom.

I did more research and reading, and what I am seeing is that the BMC is the number one thing that goes wrong on the 2002 Impala. At this point I am all ears on what to do or what might be the problem.

Thanks Joe

Nov 13, 2008.
I still don't understand what the original fault with the vehicle was? And have you replaced lock cylinder. Or ignition switch?

NOTE: Door, trunk and ignition are operated by one key. If procedure requires ignition switch lock cylinder to be replaced, new ignition switch lock cylinder should be recoded to old key.

NOTE: Passlock(tm) sensor is an integral part of ignition switch assembly

The anti-theft system has been incorporated into Body Control Module (BCM). Anti-theft system prevents vehicle operation if correct key is not used in order to start vehicle. Ignition key turns ignition lock cylinder. Cylinder rotation produces an analog voltage code in Passlock(tm) sensor. This voltage code is received by BCM. BCM compares voltage code to previously learned voltage code. If codes match, a class 2 message is sent from BCM to Powertrain Control Module (PCM). Message enables fuel injectors and crank relay.
The design of Passlock(tm) system is to prevent vehicle theft by disabling engine unless ignition lock cylinder rotates properly by engaging correct ignition key. System is similar in concept to passkey system. However, Passlock(tm) system eliminates need for a key mounted resistor pellet. Components of Passlock(tm) system are as follows: Ignition lock cylinder
Ignition switch
Passlock(tm) sensor
Body Control Module (BCM)
SECURITY indicator
Powertrain Control Module (PCM)
Ignition Lock Cylinder and Housing
The Passlock(tm) sensor and ignition lock cylinder are one assembly. Passlock(tm) sensor is separate from key and lock cylinder. Key and lock cylinder work together in order to determine if proper ignition key was used to start vehicle.
In event of an open Class 2 serial data line between BCM and PCM, vehicle will become fail-enabled if PCM has already received password from BCM for that ignition cycle (engine running). When this happens, SECURITY indicator will illuminating PCM will become fail-enabled for future ignition cycles.
If a failure in Class 2 serial data line occurs before ignition cycle, when PCM is not fail-enabled, PCM will never receive a valid password in order to enable fuel injectors and crank relay and vehicle will not start.
Ignition Switch
The electrical switching portion of ignition lock cylinder assembly is separate from key and lock cylinder. Electrical switch portion and key and lock cylinder synchronize and work in conjunction through action of mechanical assembly between two components.
Passlock(tm) Sensor
The Passlock(tm) sensor contains 2 hall effect sensors. Tamper hall effect sensor is on top. Security hall effect sensor is under tamper hall effect sensor. Both hall effect sensors monitor magnet of lock cylinder through an opening. Tamper hall effect sensor is physically placed on top of security hall effect sensor. This arrangement enables tamper hall effect sensor to engage first if an intruder attempts to bypass Passlock(tm) sensor by placing a large magnet around that area of steering column. There is a tamper resistor inside Passlock(tm) sensor in order to help prevent tamper to system. Passlock(tm) equipped vehicles have a selection of 10 different security resistors ranging from 0.5K ohms to 13.6K ohms. Installing one of the security resistors inside Passlock(tm) sensor will generate a unique Passlock(tm) code. All 10 combinations of Passlock(tm) sensor have same part number.
Body Control Module
The Body Control Module (BCM) contains anti-theft system logic. BCM reads Passlock(tm) data from Passlock(tm) sensor. If Passlock(tm) data is correct, BCM will send a class 2 message to PCM to enable fuel injectors and crank relay.
During tamper mode vehicle may start. Vehicle will then stall. If BCM receives wrong Passlock(tm) data, VTD system will immediately go into tamper mode. Tamper mode will lock-out vehicle fuel injectors and crank relay for 10 minutes. SECURITY indicator will flash while VTD is in tamper mode.
If Passlock(tm) sensor sends a correct password to BCM when ignition is in RUN position, BCM will send a fuel enable and crank relay enable signal to PCM.
SECURITY indicator
The SECURITY indicator appears on message center inside instrument cluster. If SECURITY indicator flashes or if SECURITY indicator illuminates continuously during vehicle operation, refer to system diagnosis.
Powertrain Control Module (PCM)
The PCM communicates with BCM over Class 2 serial data line. When BCM determines an incorrect password, it sends a Class 2 serial data password to PCM in order to disable crank relay and fuel injection system. If BCM receives expected voltage from Passlock(tm) sensor, BCM sends a class 2 serial data password to PCM in order to enable crank relay and fuel injection system. PCM then allows vehicle to start normally.
Fuel Lockout Cycle
The Passlock(tm) system has a lockout cycle of approximately 10 minutes. Once vehicle is in lockout cycle, vehicle remains in lockout cycle for 10 minutes, even if ignition switch is turned from RUN position to OFF position.
The Passlock(tm) system uses lockout cycle in order to synchronize all of Passlock(tm) components when any Passlock(tm) related part is replaced. Passlock(tm) system requires 3 consecutive lockout cycles in order to complete 30 minute learn procedure for a changed component.
Changing Passlock(tm) Components
The design of Passlock(tm) system is to prevent theft even if various theft deterrent parts change. Parts that can no longer be changed without possibility of going into a tamper mode are Passlock(tm) sensor, BCM and PCM.
If you replace any of these parts, vehicle may not start for 10 minutes. This is long tamper mode. If this occurs, system must go through a long tamper mode cycle. During this time SECURITY indicator will be flashing for a full 10 minutes and DTC B3031 will be set. BCM and PCM require a full 10 minutes in order to complete a learn cycle. Ignition switch must remain in RUN position until SECURITY indicator stops flashing. You will need to repeat cycle if ignition switch does not remain in RUN position. When replacing any listed parts, program Passlock(tm) system. See PASSLOCK(tm) SYSTEM under PROGRAMMING.
The design of Passlock(tm) system is to prevent vehicle operation if proper ignition key is not used in order to start vehicle. Mechanical key, in normal operation, will turn ignition lock cylinder. Passlock(tm) sensor monitoring position of lock cylinder will relay Passlock(tm) data to Body Control Module (BCM). BCM will determine validity of Passlock(tm) data. BCM will send a password to Powertrain Control Module (PCM). When PCM receives correct password PCM allows crank relay and fuel injectors to operate normally. Passlock(tm) system requires PCM and BCM to communicate various functions in order to operate. These functions transmit over class 2 serial data line.
The ignition lock cylinder and keys do not contain any coded electronic components. Lock cylinder housing contains coded electronic components. Changing an ignition lock cylinder or adding a key is a purely mechanical process which does not affect vehicle anti-theft system. To add or replace a key, simply cut a new key to match existing one. If no keys are available, lock cylinder must be changed. To change lock cylinder, simply replace existing lock cylinder with one of same type.

Dave H
Nov 13, 2008.

First off thank you for helping me try and figue this problem out.

Here is the problem, My wife went to start her car last Friday, nothing happened. So when I got home I removed the battery and had it check, checked OK. So then I start looking on the internet and found a couple of web site that led me to think it was the ING switch. Well it turns out not to be the switch, so now I am looking for answers to why it still will not start.

Like I stated earlier I have checked every fuse and a few relays and nothing is coming up bad. I did find the BCM after my neighbor came over with his code reader and it said no code in the computer. But like I said he did find the BCM for me and we pulled it out and looked at it and reinstalled it and tryed it again, nothing. So now I am wondering do I buy another BCM and hope that's the problem? Or do I do something else.


Nov 13, 2008.
The passlock sensor is the electronic lock cylinder part of the switch. It will come as a ignition lock cylinder kit and sensor. You can purchase it at the dealer. It will need programming when repairs are completed. It will not start until programmed.

Nov 14, 2008.

It's the part I have circled.

Nov 14, 2008.

Like I have been saying all along if you have replaced the part that DENNY P has circled for you then the vehicle needs to be programmed on a computer so the new part works. If you have only replaced the KEY BARREL part. Then it doesn't need programming. But I think we then have to find out why the car did not start in the first place? I don't think I would have replaced the ignition lock without doing some other diagnostics first, please let us know the actual PART you have replaced?

Dave H
Nov 14, 2008.
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