Tachometer Inspection; Tachometer Does Not Operate - Honda GL1800 Service Manual

TACHOMETER
INSPECTION

Tachometer does not operate

1. Check that the speedometer, coolant tempera-
ture gauge and fuel gauge operate properly.
• If they do not function, check the power
source
(page 20-17).
• If they function properly, go to step 2.
2. Remove the combination meter (page 20-17).
Connect the peak voltage tester or adaptor
probes to the Yellow/green (+) and Green (–) wire
terminals of the combination meter 20P black
connector.
TOOLS:
Peak voltage tester (U.S.A. only) or
Peak voltage adaptor
with commercially available digital multimeter
(impedance 10 MΩ/DCV minimum)
Start the engine and measure the tachometer
signal peak voltage.
PEAK VOLTAGE: 10.5 V minimum
• If the measured value is more than 10.5 V,
replace
(page 20-19).
• If the measured value is less than 10.5 V,
replace the engine control module (ECM).
• If there is no voltage, go to step 3.
3. Remove the top shelter (page 2-12).
Disconnect the engine control module (ECM) 22P
gray connector.
4. Check the Yellow/green wire for open or short
circuit as follows:
– Check for continuity between the combination
meter and ECM connectors.
There should be continuity.
– Check for continuity to ground.
There should be no continuity.
• If the Yellow/green wire is OK, replace the
ECM.
line and sensor ground
07HGJ-0020100
the meter/gauge
LIGHTS/METERS/SWITCHES
line
METER 20P BLACK CONNECTOR
(viewed from the terminal side)
assembly
CM 22P GRAY CONN CTOR
ellow/green
ECM 22P GRA CONNECTOR
(viewed from the terminal side)
ellow/green
Green
20-21