Summarized EEC-IV logic for the TPS......
The EEC-IV will check for the following:
- Minimum voltage at closed throttle over .49 vdc. , less than .49 and codes 23 and 63 will set as failures.
- Max voltage closed throttle should not exceeed 1.2 vdc, or codes 23 & 53 will set as failures.
- TPS voltage between .5vdc and 1.19 = no codes, TPS
...then
- Closed throttle TPS value is reset by the system to the
lowest value read when ignition is turned on every time. Or as explained by the EEC-IV
RATCH algorithm:
The variable RATCH is the output of a ratchet algorithm which continuously seeks the minimum throttle angle corresponding to a CLOSED THROTTLE position. This alleviates the necessity to set the throttle position sensor at an absolute position and compensates for system changes and differences between vehicles. The ratchet algorithm uses filtered throttle position for the determination of RATCH.
- A voltage increase of .04 vdc from the minimum registered will id part throttle status.
- Minimum WOT value of 3.21 vdc (.5 + 2.71) and not higher than actual Voltage REFerence (VREF) generated by the ECM to access WOT strategy.
FYI....This does not include the other registers and functions, the system uses to id acceleration, deceleration, cruise...etc, like:
APT = At Part Throttle flag
The value of APT is determined by a logic. Briefly, throttle angle breakpoints, in terms of counts, are used to define the CLOSED/PART_THROTTLE and PART/WIDE_OPEN_THROTTLE transitions.
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OLDTP = Previous TP sensor value, counts.
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TAR = Throttle Angle Rate of change, deg/sec.
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TP = Throttle position sensor.
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FN331B = A multiplier as a function of the present throttle angle minus the lowest measured throttle angle (TP - RATCH)
- Etc, etc, etc
Adjusting the TPS is a myth....or more proof is needed?