2002 DODGE RAM Service Repair Manual

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DODGE RAM 2002  Service Repair Manual HARD WIRED OUTPUTS
The hard wired outputs of the CTM include the fol-
lowing:
²CCD bus± - high-line/premium version only
²CCD bus+ - high-line/premium version only
²Courtesy lamp switch output - h

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DODGE RAM 2002  Service Repair Manual (4) Turn the ignition switch to the On position. For
a base version CTM, check for battery voltage at the
fused ignition switch output (st-run) fuse (Fuse 11 -
10 ampere) in the JB. For a high-line/pr

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DODGE RAM 2002  Service Repair Manual (5) Disconnect the instrument panel wire harness
connector(s) (one connector for the base version CTM,
two connectors for the high-line/premium version)
from the CTM connector receptacle(s).
(6) Remov

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DODGE RAM 2002  Service Repair Manual In addition to reducing wire harness complexity,
component sensor current loads and controller hard-
ware, multiplexing offers a diagnostic advantage. A
multiplex system allows the information flowing

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DODGE RAM 2002  Service Repair Manual BUS BIAS AND TERMINATION
The voltage network used by the CCD data bus to
transmit messages requires both bias and termina-
tion. At least one electronic control module on the
data bus must provide a v

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DODGE RAM 2002  Service Repair Manual BUS MESSAGE CODING
The first part of a data bus message has an Iden-
tification (ID) byte. The ID byte contains message
priority, message identification, message content and
message length information

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DODGE RAM 2002  Service Repair Manual MESSAGE IDENTIFICATION
Because messages are broadcast over the data bus,
all modules can receive them, yet not all modules
need all messages. In order to enhance microproces-
sor speed, unneeded messa

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DODGE RAM 2002  Service Repair Manual DIAGNOSIS AND TESTING - CCD DATA BUS
CCD BUS FAILURE
The CCD data bus can be monitored using the
DRBIIItscan tool. However, it is possible for the
data bus to pass all tests since the voltage parame-