With Impulse Counter
Testing with the impulse counterNotes on impulse readout
If the impulse readout displays no malfunctions when there is a driveability complaint, then the following function tests should be performed:
Electronic idle speed control (ELR), EGR system and (on the 602 engine) P2-control system.
Readout number 1 means no malfunction was detected in the electronic system. All other numbers are correlated to a particular component or faulty circuit.
The numbers from 1 to 13 (for engine 603) or 1 to 15 (for engine 602) appear on the display screen of the impulse counter.
If the U-Batt LED illuminates after hookup, then the impulse counter and the supply voltage to the impulse counter are in order.
Displaying the malfunction memory
1 Connect the impulse counter according to the connection diagram. Scan Tool Connecting (Connection and Use of Test Equipment)
Note:
The U-Batt LED in the display must illuminate; if not:
a) Check the impulse counter's fuse.
b) Check from test connector (X11/4) socket 1 to battery positive (should be 11 - 14 volts).
c) Check from test connector (X11/4) socket 4 to socket 1 (should be 6 - 12 volts).
2 Engine at idle speed.
3 Push the Start button between 2 and 4 seconds.
4 Scan the impulse readouts displayed and write them down. Readout 1 means no malfunctions stored. Any number greater than 1 means one or more malfunctions are stored in the system.
5 Push the Start button again, between 2 and 4 seconds. If there are no malfunctions in the system, the previous display will be repeated. If a malfunction is stored, its malfunction code will be displayed.
6 Repeat step 5 until the first malfunction is displayed again.
7 Run engine at 900 rpm for at least 5 seconds and push Start button again for 2 to 4 seconds while maintaining engine speed at 900 rpm.
8 Correct the malfunctions written down (impulse readouts), following the troubleshooting sequence.
9 Perform tests of the individual components.
Erasing the malfunction memory
After a malfunction has been repaired, the impulse display must be erased this way:
^ Push the Start button and read out the malfunction that has been removed. Then hold the Start button for 6 to 8 seconds.
Note:
^ Each malfunction displayed must be erased one at a time.
^ Once a malfunction is removed and the display erased, the malfunction code does not appear as a displayed malfunction readout any longer.
^ If there is a readout of any number greater than 1, there are additional malfunctions in the system.