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:
Check and replace ecu
Notice:
start an inspection of the connector from the backside
of the connector on the wire harness side with
the connector connected to the ecu.
When no measurement condition is specified, perform
the inspection with the engine stopped and also
the ignition switch on.
First check the ec ...
Emergency towing
If a tow truck is not available in an emergency, your vehicle may be temporarily
towed using a cable or chain secured to the emergency towing eyelet. This should
only be attempted on hard surfaced roads for short distances at low speeds.
A driver must be in the vehicle to steer and operate the ...
Radiator assy
Replacement
1. Drain coolant
2. Separate radiator hose inlet
3. Separate radiator hose outlet
4. Separate oil cooler inlet tube no.1
5. Separate oil cooler outlet tube no.1
6. Remove radiator assy
disconnect the fan motor connector.
disconnect two clamps for wire–harness from ...