AP50-AP60 FAULT FINDING - EXISTING INSTALLATION

AP50-AP60 FAULT FINDING - EXISTING INSTALLATION
AP50 – AP60 FAULT FINDING – EXISTING INSTALLATION
This Bulletin covers AP50 and AP60 models which are identified by a grey plastic
Electronic Module with a black printed label showing a vehicle speedometer image in
lower left corner. This module would normally be mounted behind the vehicle
dashboard and has the Cruise Control wiring harness connected with a multi pin
plug. If you can locate two Brown wires (one with a White trace line) at the vehicle
brake lamp switch they will lead you to this module.
AP50 ELECTRONIC MODULE
AP60 ELECTRONIC MODULE
If your Cruise Control has stopped working for no apparent reason there are some
specific areas we should review before proceeding to Diagnostic Tests.
DOES THE CRUISE CONTROL STILL TURN ON?
When you switch the Cruise Control ON (with vehicle ignition on or engine running)
does the LED light on the switch go RED in colour? If not there is a circuit
protection fuse in the Cruise Control Orange wire, please check this has not blown.
THE IMPORTANCE OF THE VEHICLE BRAKE LIGHT CIRCUIT
Our Diagnostic Test will check correct operation of the brake pedal switch but not the
circuit resistance value, so have you stood at the rear of vehicle while another
person presses the brake pedal and checked all brake lights are working? A blown
brake light bulb or circuit fault will prevent the Cruise Control from engaging. Have
you changed the factory brake lamps from bulb type to LEDs? If your vehicle has
been fitted with LED brake lamps you will need to increase the resistance of the
brake lamp circuit, please refer to LED Brake Lamp Tech Bulletin. Note this does
not refer to a third LED brake lamp (such as rear window or spoiler mount) if the
primary lamps are still bulb-type.
CONSIDER IF ANY WORK HAS BEEN DONE ON THE VEHICLE SINCE LAST
USE OF CRUISE CONTROL
There are too many options to detail, but it may be that work done on the vehicle
since the last successful use of the Cruise Control could have inadvertently affected
its operation. Please carefully think back about any work that has been done
regardless of whether you feel this is relevant. For example, and accessory may
have been fitted and connected to the Cruise Control Orange power or Green earth
wires and altered the voltage or resistance values, so this is worth careful
consideration.
PRIMARY WIRING CONNECTIONS
There are wiring connections that must be correct for reliable Cruise Control
operation. Further, these connections should be soldered and insulated to avoid
potential problems. Using scotch-lock or crimp connectors, or twisting wires and
wrapping with insulation tape will create problems, the only question is how quickly.
Orange power wire – should be connected to the ignition switched wire at the rear
of ignition key barrel. Simply probing with a test light or multi meter and connecting
to any ignition switched wire is not suitable. If you cannot access the rear of the key
barrel locate the primary ignition wire at the fuse panel and connect there.
Green earth wire – must be connected to an independent earth point on the vehicle
body. Do not connect to an existing earth where one or more wires go to earth, and
do not connect to bolt-on metal items such as steering column or dashboard frame.
Brown and Brown with White trace brake switch wires – one wire must go to
power input at the brake lamp switch on the pedal, the other to the switched output
that supplies voltage to the rear bulbs when the brake pedal is depressed. Before
engaging the Cruise Control will check firstly for 12 volts on one wire and 0 volts on
the other (disengaging when it registers voltage on both) and then it will test the 0
volt wire for circuit resistance. If both tests are ok the Cruise Control should
engage, if the module registers an incorrect reading it will not.
PERFORMING DIAGNOSTIC TESTS
When you have confirmed the above points we are ready to proceed with Diagnostic
Testing. To perform these tests you will need to look at the small red LED on our
Electronic Module (not the LED on the control switch) to confirm the module is
receiving the required input signals. Please locate the module in an appropriate
position now.
Enter diagnostic mode – We need to instruct the Cruise Control to enter this mode
rather than normal drive mode which is the default setting. To do this press and
hold the SET button while you turn the ignition key from the IGNITION OFF to the
IGNITION ON position. Release the SET button when ignition is ON. Now switch
the Cruise Control ON and the LED on the switch should go to RED colour. You
may notice the LED on the Electronic Module showing RED for approx 8 seconds
which is the module preparing for signal input, when the LED on the Electronic
Module goes off you are ready to proceed.
Diagnostic Test A – Press and hold the SET button and the LED on the Electronic
Module should go RED, release and the LED should go off.
Press and hold the RES button and the LED on the Electronic Module should go
RED, release and the LED should go off.
Press and hold the brake pedal and the LED on the Electronic Module should go
RED, release and the LED should go off.
If all inputs are correct you are ready to proceed to Diagnostic Test B-1
We are now going to test the actuator in the engine compartment, so you will need to
be in a reasonably quiet area with the bonnet and driver’s door open. Press and
hold the RES button for approx 5 seconds and you should hear the actuator valve
clicking until you release the button. Press and hold the SET button for approx 5
seconds and you should hear the actuator valve clicking until you release the button.
The pitch and volume of the two valves may be different, this does not indicate a
fault. If only one valve or neither valves click, or if a valve clicks once or twice then
stops, please contact TCAG Tech Support for advice. There is no charge for this
call.
AP50/AP60 VACUUM ACTUATOR
If both valves click you are ready to proceed to Diagnostic Test B-2
We can now perform an actuator idle-up test but please read this section carefully
before commencing test. Turn the ignition OFF and then press and hold the SET
button while you turn the ignition key from the IGNITION OFF position and start the
engine. Release the SET button when the engine is idling, switch the Cruise
Control ON and the LED on the switch should go to RED colour. You may notice
the LED on the Electronic Module showing RED as previously mentioned so wait
for the LED to go off you and are ready to proceed.
Be prepared to switch the Cruise Control OFF or press the brake pedal quickly
if the engine revs rise rapidly. Press and hold the SET button and the engine
revs should increase, but be patient as the response time is dependent on how much
manifold vacuum is available to open the throttle and can take up to 20-25 seconds.
As soon as the engine revs increase release the SET button if the revs are at a
comfortable level or switch OFF Cruise Control or press brake pedal if engine revs
are too high. The increase in revs confirms we are transmitting signal from switch to
actuator and unit is operating correctly so this test is concluded. If revs do not
increase after 30 seconds check vacuum hose (from actuator to engine) for splits,
holes or disconnection from the engine vacuum point. If there is no apparent
problem with the hose contact TCAG Tech Support for advice. There is no charge
for this call.
If you have successfully completed actuator idle-up test you are ready to
proceed to Diagnostic Test C
We are now going to test for Speed Signal input to confirm the Cruise Control is
receiving a speed reference. Drive the vehicle, preferably on a quiet road where
there is little traffic. While you must ensure you drive safely, you need to check that
the LED on the Electronic Module is flashing steadily ON/OFF/ON/OFF etc when the
vehicle has reached a speed of 15-20kph. At this speed the rate of flash will be
quite slow. As you increase the vehicle speed the rate of flash with also increase by
a modest margin. If you reach a speed of 50-60kph and the LED is not flashing
check that the magnet/s fitted to the drive shaft have not been lost and, if you have
an ohmmeter or multi meter check the Speed Sensor Coil for possible impact
damage. Place one sensor probe on each of the wiring connections on the Speed
Sensor Coil and check the resistance value. This should read 410-450 ohms
resistance. If the value is 0 ohms then the sensor coil has been damaged and
should be replaced, contact TCAG Tech Support for assistance. There is no charge
for this call.
If you have successfully completed these tests then the Cruise Control should
engage. You will need to turn the vehicle ignition OFF for approx 30 seconds to
take the Electronic Module out of Test mode and revert to normal drive mode.
Restart the engine, switch the Cruise Control ON, and road test for engagement at
different speeds starting at 50kph and working upward within local speed limits.
DISCLAIMER: Command Auto Group Pty Ltd (hereafter referred to as the company)
provides this information as a diagnostic support service to customers to assist in
fault-finding automotive Cruise Control installations. When followed correctly there
is no risk of damage to the Cruise Control, the vehicle to which it is fitted, other
property, or personal injury. The company cannot be held liable for damage, loss or
injury that occurs though product fitment to non-specified vehicles or other
mechanical or electronic devices. Further the company cannot be held liable for
damage, loss or injury that occurs from failure to understand and correctly apply this
information, or for action taken beyond that described in this or similar technical
support documents, or verbal advice provided by TCAG Technical staff.
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