DIAGNOSTICS
SERVICE MANUAL NUMBER 24
Code 21 (1 of 3): Throttle Position (TP) Sensor Circuit
ECM
MEFI 1
MEFI 2
MEFI 3
B
B
J1-13
J1-10
J1-15
J2-3
J2-26
J2-4
C
C
A
A
CIRCUIT DESCRIPTION:
The Throttle Position (TP) Sensor provides a voltage signal that changes as throttle blades
open or close. Signal voltage should vary from about .5 volts at idle to about 4.5 volts at Wide
Open Throttle (WOT).
The TP signal is one of the most important inputs used by the Electronic Control Module
(ECM) for fuel control and for most of the ECM controlled outputs.
DIAGNOSTIC AIDS:
Check for the following conditions:
•
Poor connection at ECM. Inspect harness connectors for backed out terminals,
improper mating, broken locks, improperly formed or damaged terminals, and poor
terminal to wire connection.
•
Damaged harness. Inspect the wiring harness for damage. If the harness appears to
be OK, observe the TP sensor display on the scan tool while moving connectors and
wiring harnesses related to the TP sensor. A change in the TP sensor display will
indicate the location of the fault.
•
•
The scan tool reads throttle position in voltage and percentage relative to the throttle
blade opening With ignition ON, engine OFF, throttle blades closed (idle), the voltage
should be 0.3-0.8 volts The voltage should steadily increase as the throttle is moved
toward Wide Open Throttle (WOT).
If DTC 34 is also set, check for a short to ground in CKT 416.
After repairs, clear DTC following “Clearing Trouble Codes ” procedure at the front of this
section. Failure to do so may result in DTC not properly being cleared.
Index
Page 5G-58
90-861327--1 OCTOBER 1999
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 305 CID, Mercury MerCruiser 350 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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