2180378

Check for damaged harness and terminals including rubber seals :

-. contact resistance, oxidation, corrosion, bent or broken terminals

-. harness connector connection, loose wires etc.

Check for poor connection between ECM and component :

-. backed out terminal, improper mating, broken locks and poor terminal to wire connection

ARE THE WIRES O.K ? & ARE THE CONNECTIONS O.K ?

YES

Go to "Signal Circuit Inspection" procedure

Repair as necessary and go to " Verification of Vehicle Repair " procedure

DTCs listed below is stored in the scan tool

P1634

Check items with the scan tool and the multimeter

① Wiring harness inspection

② Check the fuse

③ Check the relay resistance

Specification

Resitance : below 1 Ω for open in the wire

Resitance : infinite for short to ground in the wire

Voltage : below 0.5V for short to power in the wire

caution

Refer to the component and full circuit for connector configrations details

Disconnect the water heater relay No.1 and No.2 then turn the ignition switch ON, measure the voltage at the water relay No.1 terminal 2,5 and the water relay No.2 terminal 2,5 individually.

ARE THERE THE BATTERY VOLTAGE ?

YES

Go to step 4

Go to step 3

ARE THE FUSES BLOWN ?

YES

Repair open or short in the wire between the heater relay No.1 terminal 3 and the injector fuse (15A)

Repair open or short in the wire between the heater relay No.2 terminal 2 and the injector fuse (15A)

Repair open or short in the wire between the heater relay No.1 terminal 1 and the heater fuse No.1(60A)

Repair open or short in the wire between the heater relay No.2 terminal 5 and the heater fuse No.2(30A)

Repair open or short in the wire between the heater relay No.1 terminal 2 and the ECM terminal 23/C230-1

Replace the fuse if the fuse is broken

Replace the relay if the relay is defective after checking continuity between the relay terminal 2 and terminal 3 for the water heater relay No.1

Replace the relay if the relay is defective after checking continuity between the relay terminal 2 and terminal 4 for the water heater relay No.2. For more detailed information, Go to "Component Inspection" procedure

Go to step 4

Start the engine for checking the relay operation.

caution

To be sure the water heater relay test, the coolant should be below 65℃(149℉) at least.

ARE THERE THE HEATER RELAYS ON ?

YES

Go to "Verification of Vehicle Repair" procedure

Go to step 6

Connect the CH A,B probe of scan tool to the ECM terminal 23/C230-1 and the water heater relay terminal 1 for the water heater relay No.1 or No. 2 individually in order to check the signal waveform.

10.

Check the signal waveform after starting the engine

11.

IS THERE THE SIGNAL WAVEFORM DISPLAYED ?

YES

Go to "Verification of Vehicle Repair" procedure

Recheck open or short in the wire between the water heater relay No.1 terminal 2 and ECM terminal 23/C230-1.

Recheck open or short in the wire between the water heater relay No.2 terminal 4 and the ECM terminal 23/C230-1

Replace a known - good ECM and recheck. If the problem is verified, replace the ECM.

YES

Go to "Verification of Vehicle Repair" procedure