Mar 042012
 

I have a 96 thunderbird that will turn over but will not idle. just misfires/backfires and dies. I have an OBDII and hooked up and got the reading P1390 octane sensor out of range / open circuit, or something of that nature. I was wondering if this could be my problem and if so how should I go about fixing it?

  One Response to “1996 Ford Thinderbird Crank no start condition”

  1. P1390 FORD Octane Adjust Out of Self-Test Range

    P1390 indicates that some one has removed the octane adjust shorting bar from the computer system here is a location chart and some test procedures.
    FG1 DTC P1390: VISUALLY INSPECT OCTANE ADJUST IN-LINE CONNECTOR
    Diagnostic Trouble Code (DTC) P1390 indicates OCT ADJ shorting bar is not in or the OCT ADJ circuit is open.
    Key off.
    Visually inspect in-line connector.
    Is shorting bar removed?
    Yes: GO to FG2 .No: GO to FG4 .
    FG2 CHECK FOR MODIFICATION DECAL
    Is there a modification decal attached to the vehicle indicating that OCT ADJ shorting bar was removed?
    Yes: Testing complete. If vehicle has spark knock concern, RETURN to Section 4A .NO:GO to FG3 .
    FG3 CHECK FOR DTC P1390
    Replace OCT ADJ shorting bar.
    Key off.
    Connect Scan Tool.
    Activate Key On Engine Off Self-Test.

    Is DTC P1390 present?
    Yes: GO to FG4 .NO: Testing complete. EEC system OK.
    FG4 CHECK CONTINUITY OF OCTANE ADJUST CIRCUIT
    Note: There should be continuity from OCT ADJ circuit through the in-line connector and shorting bar to SIG RTN circuit.
    Key off.
    Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
    Install breakout box, leave PCM disconnected.
    Measure resistance between Test Pin 91 and OCT ADJ Test Pin 30 at the breakout box.

    Is the resistance less than 5.0 ohms?
    Yes: REPLACE PCM. REMOVE breakout box. RERUN Quick Test.
    NO: SERVICE open OCT ADJ circuit or shorting bar or SIG RTN circuit. REMOVE breakout box. RERUN Quick Test.
    FG5 CHECK FOR DTC P1390
    Start engine and idle vehicle at operating temperature.
    Key off.
    Connect Scan Tool.
    Activate Key On Engine Off Self-Test.
    Is DTC P1390 present?
    Yes: GO to FG1 .NO: GO to FG6 .
    FG6 VERIFY IN-LINE CONNECTOR SHORTING BAR IS INSTALLED
    Key off.
    Visually inspect OCT ADJ in-line connector.

    Is shorting bar installed?
    Yes: GO to FG8 NO: GO to FG7 .
    FG7 CHECK FOR MODIFICATION DECAL

    Is there a modification decal attached to vehicle
    indicating that OCT ADJ shorting bar was removed?
    Yes: GO to FG10 .NO: REPLACE shorting bar. RETURN to Section 4A to address spark knock concern.
    FG8 CHECK FOR TSB

    Is there a Technical Service Bulletin (TSB) authorizing removal of the shorting OCT ADJ bar?
    Yes: GO to FG9 .NO: RETURN to Section 4A to address spark knock concern.

    FG9 REMOVE OCT ADJ SHORTING BAR
    Remove OCT ADJ shorting bar only if there is a TSB authorization.
    Drive vehicle to verify spark knock.
    Is spark knock present?
    Yes: GO to FG10 .NO: Testing complete. EEC system OK.
    FG10 CHECK OCTANE ADJUST CIRCUIT FOR A SHORT TO GROUND
    Key off.
    Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
    Install breakout box, leave PCM disconnected.
    Measure resistance between OCT ADJ circuit at the in-line connector and Test Pins 51, 91 and 103 at the breakout box.
    Is each resistance greater than 10,000 ohms?
    Yes: GO to FG11 .NO: SERVICE short circuit. REMOVE breakout box. If spark knock is still present, RETURN to Section 4A .
    FG11 CHECK PCM INTEGRITY
    Key off.
    OCT ADJ shorting bar removed because of TSB authorization.
    Breakout box installed, PCM connected.
    Key on.
    Measure voltage between OCT ADJ circuit and Test Pins 51 and 103 at the breakout box.
    Is voltage greater than 4.0 volts?
    Yes: REMOVE breakout box. If spark knock is still present, RETURN to Section 4A .NO: REPLACE PCM. REMOVE breakout box. If spark knock is still present, RETURN to Section 4A .

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