[xj-s] XJS X300 4.0 high idle fix continued 1995,1996

#4 continued… Find the Black/Yellow wire on the RED (low
power) connector on the ECM (located behind the right front
passenger footwell side kick. Cut the wire 1’’ from the
connector. Connect the other end of the shielded wire to
the 1’’ stub. NOW, take the shilding wire and connect it to
a good chassis ground with a separate wire and lug. Tape
all connections as described herein. Now, take a Digital
Volt Meter (DVM), place it on 20 volts DC, connect the
Common test lead to a chassis ground in the Passerger foot
well and push the positive probe end into the Red low power
connector Black/Yellow wire plug. With everything
connected, turn the key to the on position and record the
voltage reading. IT should be .5 to .9 volts. NOW, slowly
push the accelerator all the way to the floor. The DVM
should read an increase in voltage VERY SMOOTHLY! When the
pedal hits the floor, you should see 4.30 to 5 volts. If
the base or peak voltage is out of place, you need a new TPS

  1. Confirm that the Bellows between the MAS and the
    throttle body is not cracked. Typically, the oil residue
    from the intake system starts to degrade this Bellows on the
    bottom side. It is important that there is no air leak on
    this connection. ALSO, make sure that the throttle
    butterfly is fairly clean and that it easily springs back to
    closed. ON this AJ16 engine, you should have .002 or less
    clearance between the butterfly and throttle housing. If
    there is more, someone set it to AJ6 specs. NOTE: Jaguar
    Tech Bulletin #17-11 is a kit to modify the crankcase
    breather system to reduce the oil residue that clogs the
    throttle body. I highly recommend this kit;

  2. If you have a bad MAS, look to a LandRover Discovery
    1996 for the replacement. It is half the price and is
    identical! YOu only need a new MAS if the Diagnosis code
    P0101,P0102 and P02103 are stored!!! Don’t get ripped off;

  3. NOW for the important thing!!! In the left side of the
    trunk, above the wheel well, you will see the Cruise Control
    Module (large aluminum box). Above that box is a relay and
    two black boxes. One is a timer with a plug that looks like
    a relay plug. The other is the important one. It is the
    speed sensor modulator! The SSM has two small plugs
    connected. One plug has a white shielded wire that goes to
    the sensor located on the rear of the differential. CHECK
    this wire for visual cuts, crimps, stretch marks, etc.
    Cleck where it goes through a rubber bulk head boss on the
    front side of the trunk. Check under the car for any damage
    from the exhaust, etc. Now, make sure this wire is routed
    along the front side of the trunk and in FRONT of the left
    1/4 panel support and not attached to ANY OTHER WIRE OR
    HARNESS with tape, zip tie or other device. Look up in the
    area where the SSM is located. Make sure NO wires are
    crossed. If the wires to the black timer are wrapped around
    the harness, straighten it out. If the Other SSM wire is
    tied to any other harness wire or ----
    –Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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