SPN 105, FMI 0 - IAT Higher Than Expected Stage 2

SPN 51, FMI 1 - TPS1 % Lower Than TPS2 %

Key On, Engine Off System Mode=”Stopped”

Enable ‘DBW Test’ mode Slowly depress FPP sensor

NOTE: To sweep throttle on stationary applications, go to DBW page and type desired throttle opening % in the TPS Command box.

Is TPS1 and TPS2 difference more than 20%? Yes

No

Intermittent Problem Key Off Disconnect throttle from harness Key On, Engine Off System Mode=”Stopped” Enable ‘DBW Test’ mode

Is the voltage for both TPS1 and TPS2 < 0.100 VDC? Yes

No

TPS (the one over 0.1volts) is shorted to voltage in the harness Faulty ECM Connect TPS1 signal to the 5V reference at throttle connector while observing TPS1 voltage.

Repeat for TPS2

Faulty Connection at Throttle Faulty Throttle Yes Does DST display both TPS1 and TPS2 voltage over 4.90 VDC when each is connected to 5Vref?

No

Key off Disconnect wireharness header from ECM Carefully remove yellow lock from header at device output terminal CAREFULLY check resistance between TPS1 & 2 input at ECM header and signal at device. NOTE: DO NOT INSERT

probe or object into terminals as this will cause the terminal to spread and may no longer make contact with ECM pin. Spread pins will void warranty! Probe on the side of terminal.

TPS1 or TPS2 signal shorted to ground in harness Faulty ECM connection Faulty ECM Yes Are both resistances < 5 ohms?

No

Faulty Harness

Indmar Products 2008 All Rights Reserved 44

SPN 51, FMI 4 - TPS1 Signal Voltage Low

• Throttle Body-Throttle Position Sensor 1 • Check Condition-Key On, Engine Cranking or Running • Fault Condition-TPS1 sensor voltage lower than the limit defined in the diagnostic calibration • Corrective Action(s): Sound audible warning or illuminate secondary warning lamp, shutdown engine • Non-emissions related fault

The throttle controls the airflow through the engine, directly affecting the power output of the engine. When the throttle is electronically controlled in an Electronic Throttle Body it can be used to control the idle stability and limit engine speed based on operating conditions.

The Throttle Position Sensor uses either 1) a variable resistor and voltage divider circuit or 2) a non-contact hall-effect sensor to determine throttle plate position, and is located within the throttle body. The output of the TPS is linear with angular position. The TPS input(s) provide angular position feedback of the throttle plate. In mechanical throttle bodies this sensor is typically used to help improve return-to-idle governing when working in combination with an Idle Air Control motor. In an Electronic Throttle Body multiple position feedback sensors (usually two counteracting potentiometers/hall-effects) are used to perform speed governing with improved safety and redundancy.

This fault will set if TPS1 voltage is lower than the low voltage limit as defined in the diagnostic calibration at any operating condition while the engine is cranking or running. The limit is generally set to 4.90 VDC. In many cases, this condition is caused by the TPS sensor being disconnected from the engine harness, an open-circuit or short-to-ground of the TPS circuit in the wireharness, or a failure of the sensor. This fault should be configured to trigger an engine shutdown and the engine will not start with this fault active.

Indmar Products 2008 All Rights Reserved 45