What PCM pin does the knock sensor connect to on the 4.9L?

The Knock Sensor (KS) connects through connector C1009 on circuit 310 Y/R to PCM pin 23.

What wire color and circuit is the ECT sensor signal on the 4.9L?

The Engine Coolant Temperature (ECT) sensor at connector C183 uses circuit 354 LG/R (light green/red), running through C125 and C101 to PCM pin 7.

What circuit does the IAT sensor use?

The Intake Air Temperature (IAT) sensor at connector C164 uses circuit 743 GY (gray) to PCM pin 25, with signal return 359 GY/R shared through splice S138.

Which PCM pins connect to the Vehicle Speed Sensor (VSS)?

The VSS connects on circuit 676 PK/O to PCM pin 6 and circuit 679 GY/BK to PCM pin 3; details are on pages 64-1 and 64-2.

What circuits go to the VIP data link connectors?

Circuits 915 PK/LB (PCM pin 9) and 914 T/O (PCM pin 28) via connector C198, and 209 W/P (PCM pin 48) via C185 to C199.

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Ford 4.9L Engine Controls Wiring Diagram 23-5 - ECT, IAT, Knock Sensor, PCM Pins

Ford 23-5 Engine Controls 4.9L wiring diagram with knock, ECT, IAT sensors and vehicle speed sensor

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Engine controls wiring diagram for 4.9L showing knock sensor, engine coolant temperature, intake air temperature and vehicle speed sensor circuits.

AI caption August 2018 · Photo 341 of 386

This is page 23-5 of a Ford factory-style wiring diagram titled "Engine Controls, 4.9L," covering sensor circuits connected to the Powertrain Control Module (PCM). It shows the Knock Sensor (KS) at connector C1009 with circuit 310 Y/R to PCM pin 23, the Engine Coolant Temperature (ECT) sensor at connector C183 with circuit 354 LG/R to PCM pin 7, and the Intake Air Temperature (IAT) sensor at connector C164 with circuit 743 GY to PCM pin 25. Sensor signal return circuit 359 GY/R runs through splice S138 and connector C125. Inputs also include the Turn/Stop/Hazard Lamps circuit 511 LG (12V with brake pedal depressed, page 90-2) to PCM pin 2, and Air Conditioner/Heater circuits 883 PK/LB (pin 10) and 348 P (12V switch closed, pin 43, via C185) from page 54-2. Outputs/interfaces at the bottom show the Vehicle Speed Sensor (VSS, pages 64-1/64-2) on circuits 676 PK/O (pin 6) and 679 GY/BK (pin 3), plus VIP Data Link Connectors on circuits 915 PK/LB (pin 9), 914 T/O (pin 28) via C198, and 209 W/P (pin 48) via C185/C199. Callout notes explain each sensor's function: knock detection, thermistor behavior for ECT/IAT, and the PCM's control of fuel, EGR, ignition, E4OD transmission, and evaporative emissions.

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Frequently asked questions

What PCM pin does the knock sensor connect to on the 4.9L?: The Knock Sensor (KS) connects through connector C1009 on circuit 310 Y/R to PCM pin 23.
What wire color and circuit is the ECT sensor signal on the 4.9L?: The Engine Coolant Temperature (ECT) sensor at connector C183 uses circuit 354 LG/R (light green/red), running through C125 and C101 to PCM pin 7.
What circuit does the IAT sensor use?: The Intake Air Temperature (IAT) sensor at connector C164 uses circuit 743 GY (gray) to PCM pin 25, with signal return 359 GY/R shared through splice S138.
Which PCM pins connect to the Vehicle Speed Sensor (VSS)?: The VSS connects on circuit 676 PK/O to PCM pin 6 and circuit 679 GY/BK to PCM pin 3; details are on pages 64-1 and 64-2.
What circuits go to the VIP data link connectors?: Circuits 915 PK/LB (PCM pin 9) and 914 T/O (PCM pin 28) via connector C198, and 209 W/P (PCM pin 48) via C185 to C199.