Dodge Nitro. Manual - part 812

will be turned ON, then OFF again during the bulb check portion of the test to confirm the functionality 
of the LED and the cluster control circuitry.  

The TIPM sends electronic security indicator request messages to control the security indicator whenever the 
ignition switch is in the OFF position and the VTSS is arming, armed, or alarming. Whenever the ignition 
switch is in the ON or START positions, the SKREEM performs a self-test to decide whether the SKIS is in 
good operating condition and whether a valid key is present in the ignition lock cylinder. The SKREEM then 
sends the proper lamp-ON or lamp-OFF message to the Electro Mechanical Instrument Cluster (EMIC) (also 
known as the Cab Compartment Node/CCN). If the cluster flashes the security indicator upon ignition ON, or 
turns ON the security indicator solid after the bulb test, it indicates that a SKIS malfunction has occurred or that 
the SKIS is ineffective. 

For proper diagnosis of the VTSS, the SKIS, the SKREEM, the TIPM, the EMIC, the CAN data bus or the 
electronic communication related to security indicator operation a diagnostic scan tool is required. Refer to the 
appropriate diagnostic information. 

SERVICE 4WD INDICATOR 

DESCRIPTION 

SERVICE 4WD INDICATOR 

Fig. 33: Service 4WD Indicator 
Courtesy of CHRYSLER LLC 

A service 4WD indicator is standard equipment on all instrument clusters. However, on vehicles not equipped 
with the optional four-wheel drive system and electronically shifted transfer case, this indicator is electronically 
disabled. This indicator is located near the bottom of the speedometer dial face of the cluster overlay, just left of 
center. 

 

2007 Dodge Nitro R/T 

2007 ACCESSORIES AND EQUIPMENT Instrument Cluster - Service Information - Nitro

  

The service 4WD indicator consists of a stencil-like cutout of the text SERV 4WD in the opaque layer of the 
instrument cluster overlay. The dark outer layer of the overlay prevents the indicator from being clearly visible 
when it is not illuminated. An amber Light Emitting Diode (LED) behind the cutout in the opaque layer of the 
overlay causes the indicator to appear in amber through the translucent outer layer of the overlay when it is 
illuminated from behind by the LED, which is soldered onto the instrument cluster electronic circuit board. 

The service 4WD indicator is serviced as a unit with the instrument cluster. 

OPERATION 

SERVICE 4WD INDICATOR 

The service 4WD indicator gives an indication to the vehicle operator when the Totally Integrated Power 
Module (TIPM) has recorded a Diagnostic Trouble Code (DTC) for an electronic transfer case circuit or 
component malfunction. This indicator is controlled by a transistor on the instrument cluster circuit board based 
upon cluster programming and electronic messages received by the cluster over the Controller Area Network 
(CAN) data bus. 

The service 4WD indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic 
circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery 
current input on the fused ignition switch output (run-start) circuit. Therefore, the LED will always be OFF 
when the ignition switch is in any position except ON or START. The LED only illuminates when it is provided 
a path to ground by the instrument cluster transistor. The instrument cluster will turn ON the service 4WD 
indicator for the following reasons: 



Bulb Test - Each time the ignition switch is turned to the ON position the service 4WD indicator is 
illuminated for about two seconds as a bulb test.  



Service 4WD Indicator Lamp-On Message - Each time the cluster receives an electronic service 4WD 
indicator lamp-ON message from the TIPM, the service 4WD indicator will be illuminated. The 
indicator remains illuminated until the cluster receives a lamp-OFF message from the TIPM, or until the 
ignition switch is turned to the OFF position, whichever occurs first.  



Communication Error - If the cluster receives no lamp-ON or lamp-OFF messages from the TIPM for 
10 seconds, the service 4WD indicator is illuminated by the cluster to indicate a loss of TIPM 
communication. The indicator remains controlled and illuminated by the cluster until a valid message is 
received from the TIPM.  



Actuator Test - Each time the cluster is put through the actuator test, the service 4WD indicator will be 
turned ON, then OFF again during the bulb check portion of the test to confirm the functionality of the 
LED and the cluster control circuitry.  

The TIPM continually monitors the electronic transfer case control circuits and transfer case shift motor/mode 
sensor assembly to determine the condition of the system. The TIPM then sends the proper lamp-ON or lamp-
OFF message to the Electro Mechanical Instrument Cluster (EMIC). 

For proper diagnosis of the TIPM, the EMIC, the CAN data bus or the electronic communication related to 
service 4WD indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic 
information. 

 

2007 Dodge Nitro R/T 

2007 ACCESSORIES AND EQUIPMENT Instrument Cluster - Service Information - Nitro

  

SPEEDOMETER 

DESCRIPTION 

SPEEDOMETER 

Fig. 34: Speedometer 
Courtesy of CHRYSLER LLC 

A speedometer is standard equipment on all instrument clusters. The speedometer is located in the center of the 
instrument cluster, between the tachometer and the minor gauge set. The speedometer consists of a movable 
gauge needle or pointer controlled by the instrument cluster circuitry and a fixed 210 degree primary scale on 
the gauge dial face that reads left-to-right either from 0 to 120 or 140 mph, or from 0 to 240 km/h, depending 
upon the market for which the vehicle is manufactured. 

Each version also has a secondary inner scale on the gauge dial face that provides the equivalent opposite units 
from the primary scale. Text appearing on the cluster overlay below the high end of the scales abbreviates the 
unit of measure for the primary scale (either MPH or km/h ), and below the low end of the scales abbreviates 
the unit of measure for the secondary scale. 

The speedometer graphics are white, gray and black against a black field, making them clearly visible within 
the instrument cluster in daylight. When illuminated from behind by the panel lamps dimmer controlled cluster 
illumination lighting with the exterior lamps turned ON, the graphics retain their unilluminated colors and 
appearance. The orange gauge needle has internal optical illumination. Gauge illumination is provided by Light 
Emitting Diode (LED) units soldered onto the instrument cluster electronic circuit board. 

The speedometer is serviced as a unit with the instrument cluster. 

OPERATION 

SPEEDOMETER 

 

2007 Dodge Nitro R/T 

2007 ACCESSORIES AND EQUIPMENT Instrument Cluster - Service Information - Nitro

  

The speedometer gives an indication to the vehicle operator of the vehicle road speed. This gauge is controlled 
by the instrument cluster circuit board based upon cluster programming and electronic messages received by the 
cluster from the Powertrain Control Module (PCM) over the Controller Area Network (CAN) data bus. 

The speedometer is driven by an electronic stepper motor unit that receives battery current on the instrument 
cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition 
switch is in the ON or START positions. The cluster is programmed to move the gauge needle back to the low 
end of the scale after the ignition switch is turned to the OFF position. The instrument cluster circuitry controls 
the gauge needle position and provides the following features: 



Vehicle Speed Message - Each time the cluster receives an electronic vehicle speed message from the 
PCM it will calculate the correct vehicle speed reading and position the gauge needle at that relative 
speed position on the gauge scale. The cluster will receive a new message and reposition the gauge 
pointer accordingly about every 88 milliseconds. The gauge needle will continually be positioned at the 
relative vehicle speed position on the gauge scale until the vehicle stops moving, or until the ignition 
switch is turned to the OFF position, whichever occurs first.  



Communication Error - If the cluster fails to receive a speed message, it will hold the gauge needle at 
the last indication for about three seconds, or until the ignition switch is turned to the OFF position, 
whichever occurs first. After three seconds, the gauge needle will return to the left end of the gauge scale. 



Actuator Test - Each time the cluster is put through the actuator test, the speedometer needle will be 
swept to several calibration points on the gauge scale in a prescribed sequence in order to confirm the 
functionality of the gauge and the cluster control circuitry.  

The PCM continually monitors the Vehicle Speed Sensor (VSS) to determine the vehicle road speed. The PCM 
then sends the proper vehicle speed messages to the Electro Mechanical Instrument Cluster (EMIC) (also 
known as the Cab Compartment Node/CCN). 

For proper diagnosis of the VSS, the PCM, the EMIC, the CAN data bus or the electronic communication 
related to speedometer operation a diagnostic scan tool is required. Refer to the appropriate diagnostic 
information. 

TACHOMETER 

DESCRIPTION 

TACHOMETER 

 

2007 Dodge Nitro R/T 

2007 ACCESSORIES AND EQUIPMENT Instrument Cluster - Service Information - Nitro