Last post on Aug 19, 2003 at 5:37 PM
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Oldsmobile Cutlass, Electrical
Aug 17, 2003 (9:44 pm)
Well, that circuit discription says nothing about the start circuit. Unless the mysterious CKT's have something to do with it. So it's back to the drawing board....
Aug 18, 2003 (3:03 am)
Here's the theft deterrent system, interfacing the BCM and PCM. It works by disabling the fuel injectors, which is why I wanted to know whether the engine would crank over or not. If not, I'd be digging around for an aftermarket immobilizer system buried somewhere in the car.
Document ID# 468000
1998 Oldsmobile Cutlass
Vehicle Theft Deterrent (VTD) Description
Due to component variability, the vehicle theft deterrent (VTD) system must have the learn procedure performed regardless, if the vehicle starts on the first ignition cycle after a VTD repair.
All codes in the theft deterrent module must be cleared for a relearn.
The vehicle theft deterrent system is designed in order to prevent vehicle theft by disabling the fuel injectors unless the lock cylinder is correctly engaged by a mechanical key. The theft deterrent system uses the following 4 components for theft prevention:
The lock cylinder
The ignition switch
The body control module (BCM)
The powertrain control module (PCM)
When starting the engine, the PCM searches for a password from the BCM through the Class 2 serial data circuit. If the password is not recognized or not present, the PCM will disable the engine. Two modes of tamper detection are provided:
No password received The engine will start and stall quickly. SECURITY telltale will flash on the instrument panel cluster (IPC) and then stay ON steady.
Incorrect or disable password received (More than 3 invalid passwords are received) The engine is disabled for at least 10 minutes and the SECURITY telltale will illuminate solid on the IPC during the 10 minutes.
After the vehicle has passed theft detection, the PCM will continue normal operation.
The mechanical key and lock cylinder is located in the instrument panel assembly. The electrical switching portion of the assembly is separate from the key and lock cylinder. Both of the components are synchronized and work in conjunction through the action of the actuator rod assembly.
Passlockô Lock Cylinder
The Passlockô lock cylinder is a locking cylinder that turns a rotating magnet past a stationary hall effect sensor. This action creates the Passlockô cylinder data. The Passlockô cylinder data is sent to the body control module (BCM). The Passlockô lock cylinder is interfaced with the BCM via a 3-wire connection:
Powertrain Control Module (PCM)
The Powertrain Control Module (PCM) is located on the lower left side of the instrument panel.
The PCM communicates with the body control module (BCM) via serial data over the class 2 serial data bus, CKT 1807. When the BCM determines a passed theft condition, the BCM sends a coded password to the PCM. When the PCM receives the correct password, the PCM enables the fuel injection system, allowing the vehicle to operate correctly. The PCM may allow the car to start and quickly stall during a failed theft condition.
The following conditions may cause the PCM to enter a tamper mode:
A bad timing cycle
An incorrect password
If the BCM does not receive a password within a preset time window, the BCM will enter a short tamper mode. During this mode, the PCM will not allow the car to operate for 4 seconds.
If the password is incorrect, the PCM will enter the long tamper mode. In the long tamper mode, the following actions will occur:
The THEFT SYSTEM indicator will flash.
The fuel injectors will be shut off for approximately 10 minutes.
Although the vehicle may start, the engine will quickly stall due to a fuel cut-off.
In the event of an open in the serial data communication between the BCM and the PCM, the following actions occur:
The PCM will become fail-enabled if the car has already passed theft for that ignition cycle (i.e. the engine is running).
The PCM may set the diagnostic trouble codes (DTC).
The THEFT SYSTEM indicator will light continuously.
The PCM will become fail-enabled for future ignition cycles.
If a failure occurs in serial data before the ignition cycle, while the PCM is not fail-enabled, the PCM will never receive a valid password in order to enable the continued use of the fuel injectors.
Aug 18, 2003 (4:55 am)
I guess we'll just have to wait for more information as to whether the engine cranks over or not. Trying to diagnose what the fault might be is rather futile at this stage.
Aug 18, 2003 (5:10 am)
No, the engine does not crank at all.
Something else that may or may not be related is that I can move the shifter (automatic tranny) throughout the column (Park, Neutral, Drive, etc) WITHOUT needing to depress the release button on the stick. Not exactly safe if someone I or a front seat passenger were to accidentally bump it while driving.
Aug 18, 2003 (7:53 am)
Does your state have a mechanism whereby you can access the history of the vehicle, particularly previous owners' information? If so, it would be helpful to contact the previous owner and verify that no aftermarket immobilizer system was ever installed.
#13 of 17 as for CKT #
Aug 18, 2003 (9:22 am)
that's probably alldata's way of referring to the particular wire in the harness that carries a signal. each wire has a color and a circuit number in a complex engineered device such as a car. manuals like ford's also show the exact locations in the car of each connector (numbered) that the green/grey/pink wire goes to, for instance. alcan uses alldata's service information in running his business, among other sources.
if you had a manual in hand, you could easily follow that description in troubleshooting... things like replacing the relay with a similar one used for back-up lights, for instance, and sticking a meter probe into the connector to see what the voltages do when you hit the unlock button on the door and the remote. anything that doesn't look like factory harnessing (scotchtaps on the wire, for instance) is a place where you could have an open or intermittent from some hunkajunk add-on, like a twenty-buck alarm, that might have been ripped out and thrown away, and this could be a hangover from that episode.
Aug 18, 2003 (4:21 pm)
My posts weren't from Alldata, they were direct copy/paste from the General Motors 1998 Oldsmobile Cutlass repair manual CD. Our college has contracts with GM and DCM to provide their dealer service tech training for our area of southern Ontario. I've also been browsing all the appropriate factory wiring diagrams (Valley Forge type, pioneered by Ford for automotive use) for the remote entry and vehicle theft deterrent systems, looking for a common factor. Nada yet, hence my inquiry as to whether the previous owner could be contacted.
#15 of 17 steph_beer_me
Aug 18, 2003 (8:27 pm)
Seeing as there is something weird about the shifter - you can move it without depressing the release button - makes me think that some fiddling has taken place there.
Does the engine crank over in any other position other than Park and Neutral? If so, then I suspect that something is wrong with the saftey interlock circuits and might just lead you in the direction needed to solve the other problem.
Aug 19, 2003 (6:25 am)
There's no way to contact the previous owner of the vehicle (I live in Rochester, NY by the way). I did perform a CarFax search on the vehicle before I bought it and it only showed that the vehicle originated from the NYC area. Given the car theft rates down there, my guess is that there was some aftermarket immobilizer placed in the car by the previous owner. I am completely unfamiliar with this type of device (and car alarms in general). Does anyone know WHERE and WHAT I should look for to identify such a device in the car?
#17 of 17 look at the wires themselves for non-factory kit
Aug 19, 2003 (5:37 pm)
things like electrical tape or ScotchTaps or twist-on wire splicing nuts on wires into the doors or under the dash or hood. you have to tap into (or splice out parts) of the OEM harness in order to hang non-factory stuff on, with the possible exception of conversion harnesses to match non-factory radios to the factory wiring harness. a "theftproof" alarm, a remote starter to heat the thing up in winter, or an immobilizer is going to require opening a wire in the starting circuit and putting the black box in between the two ends.
tapping signals off any of the door control wires can break wire strands, even with ScotchTaps, and let moisture in to cause corrosion.
if you have these dealiebobs on the wiring, whether there are additional wires to some extra box of gizmos or not, there are chances for the control wiring to have been munged up.
it's also possible that the door switch is broken, or that wires in the bundle leaving the door and entering a harness on the car body are pinched, bared, open, or shorted from the stress of all those openings or closings.
if you DO find a box marked something like "Fail-O-Matic Car Alarm Model 666" at the end of funny-colored wires, you can always inquire of Fail-O-Matic or a local dealer how in blazes you get back to factory condition from the install.
oh, yes... the addition of trailer brake controllers raises the value of your car $2000 and make it more reliable. at least mine