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303-03-6 303-03-6 Engine Cooling DIAGNOSIS AND TESTING (Continued) PINPOINT TEST A: DTC C1774 COOLANT TEMPERATURE SENSOR OUT OF RANGE TEST STEP ACTION TO TAKE A3 CHECK CIRCUITS 3064 (BK/O) AND 3065 (LG/P) FOR OPEN(S) • Connect 104-Pin Breakout Box (BOB) to IAA module C1945; leave IAA Yes = GO to A4. module disconnected. • With key OFF, disconnect coolant temperature sensor C1966 and No = REPAIR the wire(s) in measure the resistance of the BK/O wire between BOB pin 70 and question. coolant temperature sensor C1966. • With key OFF, measure the resistance between BOB pin 95 and coolant temperature sensor C1966. • Are the resistances less than 5 ohms? A4 CHECK CIRCUITS 3064 (BK/O) AND 3065 (LG/P) FOR SHORT(S) TO GROUND • With key OFF, measure the resistance between BOB pins 70, 95, and Yes = GO to A5. ground (BOB pin 80). • Are the resistances greater than 10,000 ohms? No = REPAIR the wire(s) in question. A5 CHECK COOLANT TEMPERATURE SENSOR • With key OFF, measure the resistance between the terminals of the Yes = REPLACE the IAA module. coolant temperature sensor and compare the reading to the values below: REFER to Actual Temperature (Approximate) No = REPLACE the coolant temperature sensor. — 0 ° C (32 ° F) = 91,000-100,700 ohms — 5 ° C (41 ° F) = 71,100-78,700 ohms — 10 ° C (50 ° F) = 56,000-62,000 ohms — 15 ° C (59 ° F) = 44,400-49,100 ohms — 20 ° C (68 ° F) = 37,300-39,200 ohms — 25 ° C (77 ° F) = 28,500-31,500 ohms — 30 ° C (86 ° F) = 23,000-25,500 ohms — 35 ° C (95 ° F) = 18,700-20,700 ohms — 40 ° C (104 ° F) = 15,300-16,900 ohms — 45 ° C (113 ° F) = 12,500-13,900 ohms — 50 ° C (122 ° F) = 10,300-11,500 ohms — 55 ° C (131 ° F) = 8,600-9,500 ohms — 60 ° C (140 ° F) = 7,100-7,900 ohms • Is the resistance OK? PINPOINT TEST B: COOLANT PUMP DOES NOT OPERATE TEST STEP ACTION TO TAKE B1 CHECK FUSE AND POWER TO COOLANT PUMP RELAY • Check 20A fuse 20 in the electric vehicle power distribution box Yes = RECONNECT the coolant (EVPDB). pump relay. GO to B2. • With key OFF, remove the coolant pump relay from the EVPDB and No = REPAIR as necessary. measure the voltage between pins 85, 87 on the coolant pump relay connector and ground. (V > 10 volts) • Is everything OK? B2 CHECK COOLANT PUMP • Enter the interface adapter assembly (IAA) module active command Yes = System OK. CHECK wiring mode CLIMATE SYSTEM CONTROL and set the active command for intermittent connections. PUMP/VBC to ON. • Does the coolant pump operate? No = GO to B3. B3 CHECK POWER TO COOLANT PUMP (Continued) |