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98 olds cutlass - weird starting problem even baffling the experts - HELP!

steph_beer_mesteph_beer_me Member Posts: 8
edited March 2014 in Oldsmobile
I've got a '98 cutlass (bought used from a dealer 2 years ago) which will NOT start unless I hit the unlock button on the keychain remote. Hitting the power unlock button on the driver side door unlocks the doors, but will not allow a start. It's been this way ever since I bought the car, but it was never a concern until the other day when the remote battery went dead and we couldn't get the car started. There is no aftermarket security system on the car (to the best of my knowledge).

I've called the service departments of three different local dealers and none of them have ever heard of anything like this before. Has anyone ever heard of this before?


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    swschradswschrad Member Posts: 2,171
    sure as shooting, you have one. possibly with a feedback switch contained in the sensitive door, more likely with wiring into or to that door or with the master security/unlock module. if there are no codes in either that computer or the main computer, and the manual has not helped the experts, it's flat-rate time... time to chase all the wires in the harness, check the voltages, and/or start swapping parts.

    I'd start with the door wiring, the switch that doesn't help much, and possibly replace the lock/unlock module on that door to get those feedback switches swapped out, and go from there.
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    79377937 Member Posts: 390
    Using the remote feeds a signal directly into the computer receiver and allows the car to be started.

    It seems that hitting the power unlock button is not feeding a signal to computer and the car will not start.

    There are a lot of relays involved in the locking circuitry so I would suspect that one of them has a contact that is used to feed a signal to the computer when you hit the power unlock button. I think that you might have a defective relay.
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    alcanalcan Member Posts: 2,550
    Does the engine crank and not start, or not crank over at all?
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    79377937 Member Posts: 390
    You'll most probably find that the power unlock button is tied into the Park/Neutral enable start circuit so I would hazard a guess and say that the engine does not crank over at all. This whole string of series connected contacts eventually finds its way onto a terminal on the Engine Control Module.

    I figure that the remote receiver is putting a go signal onto the ECM directly and bypasses all those contacts which would explain the symptoms.

    It might also be possible however that instead of going to the ECM, relay logic is used throughout that entire circuit which makes the case for a faulty relay more plausible.
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    alcanalcan Member Posts: 2,550
    The remote transmitter sends a 315 MHz rolling code digital signal to the RFE reciever, which in turn communicates with the Body Control Module. I'm still looking for the common denominator.

    Document ID# 462316
    1998 Oldsmobile Cutlass
    Keyless Entry System Circuit Description

    The keyless entry system includes the following components:

    A hand-held radio transmitter
    A remote control door lock receiver
    When a button is pushed, the transmitter sends a digitally encoded radio signal to the receiver. The range of the transmitter is approximately 7 m (12 ft). The transmitter controls the following functions:

    The door locks (all doors or just the driver's door)
    The rear compartment lid release
    Door Locks
    When the transmitter UNLOCK button is pushed once, the driver's door unlocks. The remote control door lock receiver performs the following functions:

    Receives the transmitted signal
    Applies battery voltage to CKT 694
    This action applies battery voltage directly to the left front door lock motor. The left front door lock motor is grounded through the following components:

    The left instrument panel wiring harness junction block
    The door lock relay
    When the UNLOCK button is pushed twice within 5 seconds, the remote control door lock receiver applies battery voltage to CKT 694 and CKT 194. The remote control door lock receiver directly drives the driver's door motor. The door unlock relay in the left instrument panel wiring harness junction block energizes, causing the passenger doors to unlock. When the UNLOCK or the TRUNK RELEASE button is pushed, the receiver grounds CKT 395. This action turns on the interior lamps. Refer to Interior Lights Schematics in Lighting Systems.

    When the LOCK button is pushed, the remote control door lock receiver applies battery voltage to CKT 195. This action energizes the door lock relay in the left instrument panel wiring harness junction block, which locks all the doors. The left front door lock motor is grounded through the remote control door lock receiver. The other door lock motors are grounded through the door unlock relay. When the LOCK button is pushed within 5 seconds after the initial lock cycle, the horn will chirp in order to confirm the LOCKED state. The remote control door lock receiver activates the horn chirp by grounding CKT 28. Refer to Horns Schematics in Horns.

    Security Features
    In order to prevent the unwanted possibility of the transmitter signal from being recorded and retransmitted to unlock the doors, a rolling code is incorporated into the remote control door lock receiver. When the transmitter is used, the remote control door lock receiver increments the rolling code to the next code. If the transmitter is activated outside the range of the remote control door lock receiver for more than a predetermined number of actuations, the transmitter will no longer be synchronized with the remote control door lock receiver's rolling code. The transmitter will not be functional until the transmitter is resynchronized with the remote control door lock receiver. In order to resynchronize the transmitter to the remote control door lock receiver, perform the following procedure:

    Stand within the signal reception range of the remote control door lock receiver.
    Hold both the LOCK and the UNLOCK buttons for approximately 10 seconds.
    Ensure that the system produces a cycling of the locks. This action ensures that the system is now synchronized and operational.
    Rear Compartment Lid Release
    The rear compartment lid release is operated by applying battery voltage to the rear compartment lid release motor when the TRUNK RELEASE button on the transmitter is pushed. CKT 1737 must be grounded in order for the remote control door lock receiver to activate the rear compartment lid release motor. CKT 1737 is grounded when the gear selector is in one of the following positions:

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    79377937 Member Posts: 390
    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....
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    alcanalcan Member Posts: 2,550
    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.

    Ignition Switch
    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.

    Passlock™ Lock Cylinder
    The Passlock™ lock cylinder is a locking cylinder that turns a rotating magnet past a stationary hall effect sensor. This action creates the Passlock™ cylinder data. The Passlock™ cylinder data is sent to the body control module (BCM). The Passlock™ 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.
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    79377937 Member Posts: 390
    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.
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    steph_beer_mesteph_beer_me Member Posts: 8
    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.
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    alcanalcan Member Posts: 2,550
    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.
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    swschradswschrad Member Posts: 2,171
    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.
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    alcanalcan Member Posts: 2,550
    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.
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    79377937 Member Posts: 390
    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.
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    steph_beer_mesteph_beer_me Member Posts: 8
    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?
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    swschradswschrad Member Posts: 2,171
    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 ;)
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