Exploring Toyota battery/starter circuits Starter circuit inspection and testing procedures Part Il Courtesy Toyota Motor Corporation Step 1: Check cranking speed C onnect tachometer to IG-termi- nal and crank engine. Determine approximate engine temperature. Disable ignition system. Observe engine rpm while cranking the engine. Does it exceed the value listed? OK = = 60 1pm NG = < 60 rpm TACHOMETER A LINK CONNECTOR 1 DAT, 2) BATTE If the condition is intermittent, try to duplicate the problem conditions and retest. If not, go to step 2. Step 2: Check battery and cable connections Perform battery inspection and test- ing procedures (refer to step 1 in battery inspection and testing, page 14, April issue of the Exchange). Confirm good cable connections. Confirm battery state- of-charge. Confirm that battery passes a load test. CHECK CABLES CHECK CHECK CABLE @HOLDDOWN CONNECTIONS CHECK TERMINAL CORROSION CHECK ELECTROLYTE LEVEL CHECK CASE If OK, go to step 2A. If not, service or replace the battery as indicated. Step 2A: Check cranking motor cur- rent draw Check current flow through starter motor while cranking engine. Warm up the engine if possible before performing this test. Turn off all electrical loads. Connect an inductive ammeter around the negative battery cable. Disable the ignition system. Crank the engine while observing the ammeter and noting crank- ing speed. Engine type AMPS 4 cyl 130 - 150 6 cyl approx. 175 Engine Cranks Slowly Engine Does Not Crank 1. low to normal current 1. no current flow - flow - go to STEP 6 go to STEP 3 2. high current flow - 2. high current flow - go to STEP 7 go to STEP 7 Note: If the problem is intermittent or only occurs when hot or cold, these oper- ating conditions may have to be duplicated for accurate diagnosis. Step 3: Check control circuit power at starter Turn ignition switch to the start posi- tion. Connect voltmeter positive lead to terminal 50 of starter and negative lead to starter housing. Put the transmission in park or neutral. Clutch pedal fully depressed. Theft deterrent or vehicle security system de-activated. Is voltage greater than or equal to 9.1 volts? OK = 9.1 volts NG < 9.1 volts 30A ST Main Rais Theft Deterrent (TDS) If OK, there is a faulty starter or starter solenoid. If not, go to step 4. Step 4: Check control circuit voltage drop Turn ignition switch to start position. Connect voltmeter positive lead to battery post and negative lead to terminal 50. Transmission in park or neutral. Clutch pedal fully depressed. Theft deterrent or vehicle security system deactivated. Is voltage less than or equal to 0.3 volts? OK <= 0.3 volts NG > 0.3 volts Note: If voltage is approximately 12 volts, go to step 5. o—ACC eIG 1 St 4 [ew – ‘Clutch 72 Start ro sw all ae BOL 30K i ”~ ST Main tll 3 4 If OK, repair faulty solenoid ground circuit. If the voltage is greater than 0.3 volts, but less than battery voltage, go to step 4A. If the voltage is approximately 12 volts, go to step 5. Step 4A: Repair solenoid control circuit Repair high resistance wire or connec- tion between starter terminal 50 and battery positive terminal. Refer to EWD to determine switches and connections in this circuit. Check the following compo- nents and connections for high resist- ance: