RAM 2500 Truck 2WD L6-5.9L DSL Turbo VIN C (2002)
display (VFD) to perform a segment check. The self test routine can be entered by pushing and holding the trip reset button while rotating the ignition
key from the "OFF" to the "ON" position. When the word "chec" appears release the knob and the test will continue.
The Powertrain Control Module diagnostic trouble codes (P-Codes) are displayed in the cluster odometer. A diagnostic trouble code display request will
be initiated by the JTEC after 3 successive ignition cycles from "OFF" to "RUN" position. The cluster will display the received four digit P-Code for 4
seconds, then display 6 dashes and another P-Code. At the end when all the P-Codes are done the cluster will display "DONE" on the odometer.
The cluster will provide bus bias and termination and the engine controller provides a second termination. If the cluster is disconnected the bus will not
be biased.
The cluster will be service as an assembly. There will be limited parts available, bulbs and sockets, the front lens, the trip odometer stem cover and the
rear cover assembly. No internal parts of the cluster will be serviced.
Normal Operations
At key on, the cluster will light the low fuel, seat belt, check gauges, and airbag. As the key is turned farther towards the start position, the check engine,
ABS (if equipped) and brake warning lamp will illuminate. The (VFD) will indicate the mileage stored inside the cluster. If there is a bus failure and the
cluster cannot receive distance pulses from the engine controller, the cluster will display the last mileage stored until the ignition is turned off. If the
cluster is receiving bus messages but is unable to display odometer information because of an internal failure, the odometer display will be blank.
Dimming is handled by the potentiometer that controls instrumentation illumination. Also, if there is a CCD bus failure, "no bus" will be displayed on the
odometer 20 seconds after the vehicle is started.
Indicators (Hardwired)
The following indicators are hardwired in the cluster and are not part of the self-test.
*
Full Time 4WD
*
Seat Belt
*
Brake Warning
*
High Beam
*
Left Turn Signal
*
Right Turn Signal
*
Low Wash Fluid Level
*
Wait to Start
Indicators (CCD)
The cluster via CCD messages controls the following indicators. They are actuated during the self-test procedure.
*
ABS (amber)
*
Low Fuel Warning - Internally Controlled by the Cluster not CCD
*
Airbag
*
Upshift (if equipped)
*
Check Engine
*
Check Gauges
*
Cruise Control Lamp
*
Trans Temp
*
O/D Off (if equipped)
*
Water in Fuel
*
Maintenance Required (5.9 Heavy Duty only)
NOTE: THE SEAT BELT AND LOW WASHER FLUID SWITCH ARE HARDWIRED TO THE CLUSTER. THE CLUSTER THEN DECIDES IF
THE INDICATOR SHOULD BE ILLUMINATED.
Gauges
The instrument cluster will not store any DTCs. Because the engine controller PCM gathers all the gauge information and sends it to the cluster via the
bus, it is the controller's responsibility to monitor these inputs and store DTCs for them. For this reason the first time to be checked regarding a gauge
problem (except oil pressure) should be the engine controller for any DTCs relating to the gauge in question.
There are DTCs associated with all the gauges except for the oil pressure gauge. When diagnosing gauges, the input that is used for the gauge message
(fuel level sender for example) must be valid. Because of OBD II requirements, most of the information used for monitoring the OBD II system happens
to be the same information used by the controller to formulate the gauge bus message. OBD II Requirements State that the fuel level sender must be
checked for rationality. This includes determining if the sending unit voltage is too high or too low or if the voltage hasn't changed over time. If the PCM
has determined that the sender information isn't valid, it will send a diagnostic trouble code. The presence or absence of the fuel level sending code in the
PCM is an important factor to determine whether a fuel gauge problem is in the sending unit or the cluster.
The same situation is used in all cluster diagnostics related to gauge operation with the exception of the oil pressure gauge. OBD II requirements do not
