Cranking Holding Function Circuit
3UR-FE ENGINE CONTROL: SFI SYSTEM: Cranking Holding Function Circuit
- Cranking Holding Function Circuit
DESCRIPTION
The cranking holding control system provides current to the starter when the ECM detects the engine switch start signal (STSW). When the ECM performs a firing judgment, the system cuts current to the starter. When an ECM receives the STSW signal, it turns on the ACC cut, which prevents flickering of the combination meter, clock, audio system, etc. Also, the ECM sends a signal to the ECM STAR terminal. Then the STAR output signal travels through the Park/Neutral Position (PNP) switch to the starter relay, causing the starter to activate.
When the engine is cranking, the starter operation signal is sent to the ECM STA terminal.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
PROCEDURE
1. CHECK CRANKING
(a) Check the cranking of the engine.
Result
C -- CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - ECM)
B -- READ VALUE USING TECHSTREAM (STARTER SIGNAL)
A -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures
2. READ VALUE USING TECHSTREAM (STARTER SIGNAL)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Starter Signal.
(e) Check the value displayed on the Techstream when the engine switch is turned to the START.
OK:
NG -- INSPECT STARTER CUT RELAY (ST CUT)
OK -- Continue to next step.
3. INSPECT STARTER RELAY (ST)
(a) Remove the starter relay (ST) from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPLACE STARTER RELAY (ST)
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (ST RELAY - PNP SWITCH)
(a) Remove the starter relay (ST) from the engine room relay block.
(b) Disconnect the C19 PNP switch.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK STARTER RELAY (POWER SOURCE)
(a) Remove the ST relay from the engine room relay block.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STARTER RELAY (ST) - BATTERY, BODY GROUND)
OK -- Continue to next step.
6. INSPECT STARTER
(a) Inspect the starter Testing and Inspection.
NG -- REPAIR OR REPLACE STARTER Removal
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (STARTER - STARTER RELAY (ST), BATTERY)
7. INSPECT STARTER CUT RELAY (ST CUT)
(a) Remove the starter cut relay (ST CUT) from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPLACE STARTER CUT RELAY (ST CUT)
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (ST CUT RELAY - PNP SWITCH, ECM)
(a) Remove the starter cut relay (ST CUT) from the engine room relay block.
(b) Disconnect the C19 PNP switch connector.
(c) Disconnect the C53 ECM connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
9. INSPECT PARK/NEUTRAL POSITION SWITCH
(a) Inspect the Park/Neutral Position (PNP) switch.
(1) Disconnect the C19 PNP switch connector.
(2) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPLACE PARK/NEUTRAL POSITION SWITCH Removal
OK -- Continue to next step.
10. CHECK HARNESS AND CONNECTOR (PNP SWITCH - ECM)
(a) Disconnect the C19 PNP switch connector.
(b) Disconnect the A38 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Result
B -- REPLACE ECM
A -- REPAIR OR REPLACE HARNESS OR CONNECTOR
11. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - ECM)
(a) Disconnect the E4 main body ECU connector.
(b) Disconnect the A38 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
12. CHECK HARNESS AND CONNECTOR (ST CUT RELAY - PNP SWITCH, ECM)
(a) Remove the starter cut relay (ST CUT) from the engine room relay block.
(b) Disconnect the C19 PNP switch connector.
(c) Disconnect the C53 ECM connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM Removal
13. REPLACE ECM
(a) Replace the ECM Removal.
NEXT -- Continue to next step.
14. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
(a) Check the starter operation.
OK:
Malfunction has been repaired successfully.
NG -- GO TO SMART KEY SYSTEM (ENGINE DOES NOT START) Engine Does Not Start
OK -- END