Volvo 819 E - Page 101

Gr o up 28 Ignition syst ems
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220
Connect diode tester between diagnostic unrt LED and
test lead
Connect red
probe on diode tester to pin under LED
and black probe to t es t lead.
LED is ope rating correctly if diode tester gives indica-
ti on .
Replace
diagnos lic unit if no indica t ion is observed.
N19
Check for voltage at control unit
Sw i tch on ignition
Meas ure vol tag e between con trol unit connector termi-
nal 6 (blue) and ground . Vol tage should be approx .
12 V.
Switch off ignition.
N20
Check co ntrol unit ground lead
Meas ure resistance between connec tor t erminal 20
(b rown ) and ground .
Re sistance should be 0 ohm .
N21
Check temperature sensor
Measure resistance between co nne c tor te rminal 2l r edl
black) and ground .
Ohmme ter reading shou ld agree with adjoining chart .
If value is i ncorrect : Measure sensor r es istance directly
10 determ ine whether sensor or lead is faulty. Replace
sensor
or lead as appropriate .
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