DaimlerChrysler LH New Yorker 1994, Electronic Service Manual

Page: 326 / 1203

CHECKING FOR DIAGNOSTIC TROUBLE CODE
(1) When trying to verify a speed control system
electronic malfunction:
(a) Connect a DRB to diagnostic 6-way connector,
if available.
(b) The connector is located at right side of the
steering column, and at lower edge of the knee
bolster.
(c) Check that either a Diagnostic Trouble Code
34, 15 or 77 is indicated.
(d) An inoperative speed control may still occur
without either diagnostic code being indicated.
(e) With key inserted in ignition switch, cycle
switch to ON position three times. On third cycle,
leave switch in ON position.
(f) After switch has been cycled three times, ob-
serve Malfunction (CHECK ENGINE) Indicator
Lamp on instrument cluster. If a Diagnostic Trouble
Code is present, indicator will flash (blink) in a
series which will show which diagnostic code is the
problem. EXAMPLE: A series of three flashes in
rapid succession, a slight pause, then four flashes in
rapid succession would indicate diagnostic code 34.
(2) If no diagnostic code appears, or code 34 is
observed, perform:
•
The Electrical Test at Servo below and the Speed
Control Switch Test.
•
The Electrical Test at powertrain control module.
Refer to the appropriate powertrain diagnostic
manual. To determine the source of the problem.
(3) If a diagnostic code 15 is observed, perform the
test for a faulty vehicle speed sensor, refer to Group
8E, Instrument Panel.
(4) If diagnostic code 77 appears, refer to speed
control relay test.
(5) Correct any problems found when performing
these tests and recheck for diagnostic code if changes
were made.
(6) If no problems were found in step (2), replace
powertrain control module.
ELECTRICAL TEST:
Electronic speed control systems may be tested us-
ing two different methods. One involves use of a DRB.
If this test method is desired, please refer to the
Powertrain Diagnostic Test Procedures for charging
and speed control system manual.
The other test method uses a voltmeter. The volt-
meter method is described in the following tests.
If any information is needed concerning wiring, re-
fer to Group 8W, Wiring Diagrams.
CAUTION: When test probing for voltage or continu-
ity at electrical connectors, care must be taken not
to damage connector, terminals, or seals. If these
components are damaged, intermittent or complete
system failure may occur.
ELECTRICAL TESTS AT SERVO
WARNING: ON VEHICLES EQUIPPED WITH AIRBAG,
SEE GROUP 8M, RESTRAINT SYSTEMS FOR AIR-
BAG, STEERING WHEEL OR COLUMN REMOVAL
PROCEDURES.
(1) Turn ignition switch to the ON position. With
the speed control switch in the ON position, set up a
voltmeter to read battery voltage and connect the
negative lead to a good chassis ground.
(2) Disconnect the four-way connector going to the
servo (Fig. 7). Using a voltmeter, test pin 2 of the
main harness four-way connector for battery voltage.
If not OK, go to step 3. If OK, go to step 4.
(3) Perform the following tests.
(a) Disconnect the six-way connector at the stop
lamp switch and test pin 1 for battery voltage. If
voltage is OK, perform the stop lamp switch test.
(b) If the stop lamp switch tests OK, repair wire
between the servo and the stop lamp switch.
(c) If no voltage at pin 1 of the six-way stop lamp
connector, remove the ON/OFF speed control switch
on the steering wheel. Disconnect the two-way con-
nector and test pin 1 for battery voltage.
Fig. 6 Speed Control Circuit
VEHICLE SPEED CONTROL SYSTEM 8H - 5