Grand Cherokee 4WD V8-4.7L (2003)
radio, or wiring could be at fault.
On radios with an external amplifier, the term "output" refers to the circuit between the radio connector and the amplifier. The radio is capable of
monitoring only this portion and can tell nothing about the circuit between the amplifier and the speakers. Consequently, a shorted output DTC on this
type of system would only refer to this circuit. A faulty speaker could not cause this DTC.
REMOTE RADIO CONTROLS
These radios can be controlled via remote radio switches (optional). These switches are located on the back side of the steering wheel. They control
mode, preset, seek up, seek down, volume up and volume down functions.
These functions are inputs to the Body Control Module and can be read with the DRBIII. The switches are a multiplexed signal to the BCM. The radio
control MUX circuit is a 5 volt line that is pulled to ground through different value resistors built into the switches. This causes a voltage drop to be
seen by the BCM and it sends a specific message to the radio on the PCI Bus circuit. The radio then responses to the message.
This circuit is fairly simple to troubleshoot. The circuit must be complete from the switches in the steering wheel to the BCM. The ground must be
complete so that the switches can cause the voltage drop for the BCM to see. The circuit passes through the clockspring so continuity through this
devise must be verified.
CD CHANGER
The CD Changer is mounted in the cargo area of the passenger compartment on the right rear quarter panel. The CD Changer features a removable
10-CD magazine. The CD Changer receives both ground and radio switch power through the radio. The controls on the radio operate the CD Changer
through messages sent over the PCI Bus. The two-channel audio outputs of the CD Changer are hard-wired back to the radio, which then outputs the
signal through the channels to the speakers or amplifiers.
Chime System
CHIME SYSTEM
The chime system responds to requests from five modules: the Body Control Module (BCM), Electronic Vehicle Information Center (EVIC),
Mechanical Instrument Cluster (MIC), Sentry Key Immobilizer Module (SKIM) and the Powertrain Control Module (PCM). Each module monitors its
related systems and, via the PCI bus, requests the BCM to sound its internal chime as needed.
The chime will sound for the following conditions:
MIC Requested Chime Messages
-
Airbag
-
Check Gauges
-
Charging Voltage Low
-
Coolant Temp High
-
Low Oil Pressure
-
Charging Voltage High
-
Low Fuel
-
ABS
-
Low Battery Voltage
-
Water in Fuel (Diesel)
-
Low Coolant level (Diesel)
BCM Initiated Chime Messages
-
Headlamp ON with ignition OFF and driver door open
-
Key in ignition with ignition OFF and driver door open
-
Seat Belt Warning
-
Overspeed Warning (Gulf Coast Countries Only)
EVIC Chime Requested Messages
When the following messages are displayed the EVIC will send a chime request to the BCM. The BCM will respond with a series of chimes.
-
Turn signal on for more than 1.0 mile
-
Service reminder
-
Coolant level low
-
Washer fluid low
-
Tire Pressure Monitoring System alert messages (if equipped)
