Dodge RAM TRUCK 1500 1995 Service Manual page 462

8H - 8 VEHICLE SPEED CONTROL SYSTEM
B R
SPEED CONTROL DIAGNOSTIC TROUBLE COX
Diagnostic
Trouble
Code
DRB Scon Tool
Display Description of Diagnostic Trouble Code
I P No Crank Reference No crank reference signal detected during engine cranking.
Signal at PCM
15*V.
No Vehicle Speed
Sensor Signal
No vehicle distance (speed) sensor signal detected during road load conditions.
34* Speed Control
Solenoid Circuits
An open or shorted condition detected in the Speed Control vacuum or vent solenoid
circuits.
or
Speed Control
Switch Always Low
or
Speed Control
Switch Always High
Speed Control switch input below the minimum acceptable voltage.
or
Speed Control
Switch Always Low
or
Speed Control
Switch Always High
Speed Control switch input above the maximum acceptable voltage.
55*......... N / A Completion of fault code display on Check Engine lamp.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded. Cycle Ignition key as described
in manualand observe code flashed by Check Engine Lamp.
*'Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
J948H-26
SPEED CONTROL SWITCH
WARNING: B E F O R E BEGINNING ANY A I R B A G S Y S ­
TEM COMPONENT REMOVAL OR INSTALLATION,
R E M O V E AND ISOLATE THE NEGATIVE (-) C A B L E
FROM THE BATTERY, THEN WAIT TWO MINUTES
FOR S Y S T E M CAPACITOR TO D I S C H A R G E B E ­
F O R E F U R T H E R S Y S T E M S E R V I C E . THIS IS THE
ONLY S U R E WAY TO D I S A B L E THE A I R B A G S Y S ­
T E M . FAILURE TO DO THIS COULD R E S U L T IN AC­
CIDENTAL AIR B A G D E P L O Y M E N T AND P O S S I B L E
INJURY.
(1) Disconnect battery negative cable. Wait 2 min­
utes for airbag system capacitor to discharge. Re­
move speed control switch from steering wheel.
(2) Check speed control switch continuity as shown
in chart (Fig. 2). If OK, reinstall switch. If not OK,
replace switch.
STOP LAMP SWITCH
(1) Remove the stop lamp switch from the mount­
ing bracket. Refer to Group 5 - Brakes for procedure.
(2) Disconnect switch from wiring harness.
(3) Using an ohmmeter, check switch continuity
(Fig. 3) as follows:
(a) With switch plunger released, there should be
continuity between pin 5 and pin 6.
(b) With switch plunger depressed, there should
be continuity between pin 1 and pin 2.
(c) With switch plunger still depressed, there
should be continuity between pin 3 and pin 4.
CONNECTOR TERMINAL END
SWITCH
© a f f i i i u i w wmwmm
OFF
PIN 1 AND PIN 4
O N
PIN 1 AND PIN 4
PIN 1 AND PIN 2
?y.
F r
ON AND SET
ON AND RESUME
p:v : a k d PES:
z
J948H-30
Fig. 2 Speed Control Switch Continuity
(4) If the switch fails the above continuity tests, it
is faulty and must be replaced. If switch is OK, rein-