Mercury 305 CID - Page 632

ELECTRONIC FUEL INJECTION (MULTI-PORT AND THROTTLE BODY) - 5E-9190-823225--1 1096
Code 21: Throttle Position (TP) Sensor Circuit (Non Scan)
• CONNECT DVM
BETWEEN HARNESS
TERMINAL “C” AND
ENGINE GROUND.
IS VOLTAGE OVER 4
VOLTS?
YES
YES NO
NO
FAULTY CONNECTION
AT ECM
OR
CKT 416 OPEN
OR
SHORTED TO GROUND
OR
FAULTY ECM.
YES
CKT 417 SHORTED
TO VOLTAGE.
OPEN CKT 417
OR
FAULTY CONNECTION
AT ECM
OR
FAULTY ECM.
1
3
4
• CONNECT DVM FROM HARNESS TERMINAL “A”
(CKT 416) TO HARNESS TERMINAL “C” (THROTTLE
POSITION SENSOR SIGNAL, CKT 417).
IS VOLTAGE READING OVER 4 VOLTS?
• IGNITION “OFF.”
• CONNECT A TEST LIGHT
TO B+ BATTERY POSITIVE.
• TOUCH TEST LIGHT TO
HARNESS TERMINAL “C”
(THROTTLE POSITION
SENSOR SIGNAL).
IS TEST LIGHT “ON”?
• IGNITION “OFF.”
• DISCONNECT THROTTLE POSITION SENSOR
ELECTRICAL CONNECTOR.
• IGNITION “ON.”
• CONNECT A DVM FROM HARNESS TERMINAL “A”
(5 VOLT REFERENCE TO HARNESS TERMINAL “B”
SENSOR GROUND).
IS VOLTAGE READING OVER 4 VOLTS?
• CONNECT DVM FROM THROTTLE POSITION
SENSOR HARNESS TERMINAL “A” TO A GOOD
GROUND ON ENGINE.
IS VOLTAGE OVER 4 VOLTS?
YES
FAULTY CONNECTION
AT ECM
OR CKT 813 OPEN
OR
FAULTY ECM.
2
NO
NO
YES NO
• DISCONNECT ECM.
• TOUCH TEST LIGHT
CONNECTED TO B+ (BAT
TERY POSITIVE) TO
HARNESS TERMINAL “C”.
IS TEST LIGHT “ON”?
THROTTLE POSITION
SENSOR FAULTY.
YES NO
CKT 417 SHORTED
TO GROUND.
FAULTY ECM.