Speedometer/Navigation/Voice Alert - Erratic Operation

84chrysler10

Models 1984 Domestic Vehicles Equipped With Electronic Instrument Cluster, Electronic Navigator, 11- Function Electronic Voice Alert, 24- Function Electronic Monitor and/or 2.2L Electronic Fuel Injection or Turbocharged Engines Subject


Erratic Distance (Speed) Sensor Operation


Index

ELECTRICAL


Date


April 23, 1984

No.

08-07-84


P-1566-C
SYMPTOM/CONDITION

^ Electronic Instrument Clusters - Speedometer operation may be erratic (jumping from low mph to high mph at steady speed, etc.)

^ Electronic Navigator - Average speed and trip mileage can be affected.

^ 11-Function Electronic Voice Alert - Seat belt, door ajar, park brake, and all monitored systems messages may not be received.

^ 24-Function Electronic Monitor - Seat belt, door ajar, hatch ajar, and park brake messages may be inhibited.

^ EFI/Turbo Vehicles - Erratic idle only after a deceleration. (Distance ((speed)) sensor signals the logic module when EFI/Turbo vehicle is in a deceleration mode.)

Any of the above conditions may be due to a defective distance (speed) sensor, which is located in the speedometer cable.

DIAGNOSIS

The distance (speed) sensor should generate eight pulses per revolution. To check the sensor, use an ohmmeter on the lowest scale
(example: 0-2) so readings of less than 1 ohm will show clearly. Each pulse should have a value of 0.5 (1/2) ohm or less. Anything over this specification indicates too much resistance in distance (speed) sensor reed switch contacts.

NOTE: MAKE SURE OHMMETER IS CALIBRATED BEFORE PERFORMING TEST.

CAUTION: TO AVOID DAMAGE TO SPEED SENSOR, DO NOT USE TEST LAMP TO CHECK SPEED SENSOR.
One reason for distance (speed) sensor failures is tension on pigtail of the sensor. This tension may damage the internal reed switch. If sensor replacement is necessary, be sure there is enough slack in wiring so there is no tension on the sensor pigtails.

To create more slack in wiring, longer pigtail leads will be added to current distance (speed) sensor PN 4222714 (aluminum housing).

A new sensor will soon be released with a Plastic Housing (black) PN 4312186. Both sensors are interchangeable with each other.


POLICY: Information only