Toyota Corolla Repair Manual: Check open circuit
- For the open circuit in the wire harness in fig. 1, Perform a resistance check in step (b) or a voltage check in step (c) to locate the section.
- Check the resistance.
- Disconnect connectors a and c and measure the
resistance between them.
Resistance: 1 Ω or less
Hint
: measure the resistance while lightly shaking the wire harness vertically and horizontally. In the case of fig. 2: Between terminal 1 of connector a and terminal 1 of connector c " 10 kΩ
or higher between terminal 2 of connector a and terminal 2 of connector c " below 1 Ω
therefore, the cause is an open circuit between terminal 1 of connector a and terminal 1 of connector c.
- Disconnect connector b and measure the resistance
between the connectors.
In the case of fig. 3: Between terminal 1 of connector a and terminal 1 of connector b1 " below 1 w between terminal 1 of connector b2 and terminal 1 of connector c " 10 kw therefore, the cause is an open circuit between terminal 1 of connector b2 and terminal 1 of connector c.
- Check the voltage.
- In a circuit in which voltage is applied (to the ecu
connector terminal), an open circuit can be checked
by conducting a voltage check.
As shown in fig. 4, With each connector still connected, measure the voltage between the body ground and terminal 1 of connector a at the ecu 5 v output terminal, terminal 1 of connector b, and terminal 1 of connector c, in that order.
- If the results are: 5 v: between terminal 1 of connector a and body ground 5 v: between terminal 1 of connector b and body ground 0 v: between terminal 1 of connector c and body ground therefore, the cause is an open circuit in the wire harness between terminal 1 of connector b and terminal 1 of connector c.
Basic inspection
Resistance measuring condition of electronic parts
unless stated, all resistance is measured at an ambient
temperature of 20 c (68 °F). As the resistance
may be outside the specifi ...
Check short circuit
If the wire harness is ground shorted as shown in fig. 5,
Locate the section by conducting a resistance check with
the body ground in step (b).
Check the resistance with the body grou ...
Other materials:
Monitor description
While the engine is being cranked, the battery positive voltage is applied to
terminal sta of the ecm.
If the ecm detects the starter control signal (sta) while the vehicle is
driving, it will conclude that there is
a fault in the starter control circuit. The ecm will turn on the mil and a d ...
On–vehicle inspection
Notice:
”cold” and ”hot” in these sentences express the temperature of the coils
themselves. ”Cold” is from
–10 c (14 f) to 50 c (122 f) and ”hot” is from 50 c (122 f) to 100 c (212 f).
1. Inspect ignition coil (with igniter) and spark test
confirm dtc.
Notice:
if dtc is indicat ...
Problem symptoms table
If a normal code is displayed during the dtc check but the problem still
occurs, check the circuits for each
problem symptom in the order given in the table below and proceed to the
relevant troubleshooting page.
Notice:
when replacing skid control ecu, sensor or etc., Turn the ignition swi ...
