Cranking Holding Function Circuit
2GR-FE ENGINE CONTROL SYSTEM: 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 ignition switch's 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 ST CUT relay, which prevents flickering of the combination meter assembly, clock, audio system, etc. Also, the ECM sends a signal to the ECM's STAR terminal. Then the STAR output signal travels through the park/neutral position (PNP) switch to the ST relay, causing the starter to activate.
When the engine is cranking, the starter operation signal is sent to the ECM's STA terminal.
WIRING DIAGRAM
Refer to DTC P0617 SFI System.
INSPECTION PROCEDURE
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
PROCEDURE
1. CHECK CRANKING
(a) When starting the engine, check whether the starter motor starts.
NG -- READ VALUE USING TECHSTREAM (STARTER SIGNAL)
OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures
2. READ VALUE USING TECHSTREAM (STARTER SIGNAL)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Select the following menu items: Powertrain / Engine / Data List / All Data / Starter Signal.
(e) Check the value displayed on the Techstream when the engine switch is turned on (IG) and the engine is started.
OK:
Result:
B -- INSPECT ST RELAY
A -- Continue to next step.
3. INSPECT ECM (STSW VOLTAGE)
(a) Disconnect the ECM Connector.
(b) Turn the engine switch on (IG).
(c) Measure the voltage between the terminal of the ECM connector and body ground while cranking the engine.
Standard voltage:
(d) Reconnect the ECM connector.
NG -- CHECK HARNESS AND CONNECTOR (POWER SOURCE CONTROL ECU - ECM)
OK -- Continue to next step.
4. INSPECT ECM (STAR VOLTAGE)
(a) Remove the ST CUT relay from the engine room R/B.
(b) Turn the engine switch on (IG).
(c) Measure the voltage between the terminal of the engine room R/B and body ground while cranking the engine.
Standard voltage:
(d) Reinstall the ST CUT relay.
NG -- CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH - ST RELAY)
OK -- Continue to next step.
5. INSPECT ST CUT RELAY
(a) Remove the ST CUT relay from the engine room R/B.
(b) Measure the resistance between the terminals.
Standard resistance:
(c) Reinstall the ST CUT relay.
NG -- REPLACE ST CUT RELAY
OK -- Continue to next step.
6. INSPECT PARK/NEUTRAL SWITCH ASSEMBLY
(a) Inspect the park/neutral position switch assembly Component Tests and General Diagnostics.
NG -- REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY Removal
OK -- CHECK HARNESS AND CONNECTOR (STARTER SIGNAL CIRCUIT)
7. INSPECT ST RELAY
(a) Inspect the ST relay Testing and Inspection.
NG -- REPLACE ST RELAY
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH - ST RELAY)
(a) Disconnect the park/neutral position switch connector.
(b) Remove the ST relay from the engine room R/B.
(c) Measure the resistance between the terminals.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reinstall the ST relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
9. INSPECT ENGINE ROOM RELAY BLOCK (ST RELAY VOLTAGE)
(a) Remove the ST relay from the engine room R/B.
(b) Turn the engine switch on (IG).
(c) Measure the voltage between the terminal of the engine room R/B and body ground while cranking the engine.
Standard voltage:
(d) Reinstall the ST relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
10. INSPECT STARTER ASSEMBLY
(a) Inspect the starter assembly Testing and Inspection.
NG -- REPAIR OR REPLACE STARTER ASSEMBLY Removal
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ST RELAY - STARTER, STARTER - BATTERY)
11. CHECK HARNESS AND CONNECTOR (POWER SOURCE CONTROL ECU - ECM)
(a) Disconnect the power source control ECU connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance between the terminals.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the power source control ECU connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- GO TO SMART KEY SYSTEM How To Proceed With Troubleshooting