What does the Intake Air Temperature (IAT) sensor do according to this diagram?

It is a thermistor that decreases resistance as intake air temperature increases. The PCM uses the voltage drops to calculate idle fuel delivery, spark timing and EGR control.

Which fuse powers the RH heated oxygen sensor on the 5.8L California engine?

Fuse E, a 15A fuse in the engine compartment fuse box, hot in run (see Power Distribution page 13-4), on circuit 298 P/O with 12V in RUN.

What wire colors and PCM pins are used for the IAT sensor?

The IAT sensor uses circuit 743 GY to PCM pin 25 and circuit 359 GY/R (signal return) that also goes to PCM pin 46.

How is the RH heated oxygen sensor (HO2S) grounded?

Through circuit 57 BK, via splice S100, to ground G101 (see Grounds page 10-2).

What circuit carries the HO2S signal to the PCM?

Circuit 74 GY/LB runs from the HO2S through connectors C107F/C107M to PCM pin 44.

Home/ Registry/ Ford/ Bronco/ 1992-1996/ “Buckin Bronco”/ Photo supermotors.net/registry/media/1149759

Ford Bronco 5.8L California Engine Controls Wiring Diagram - IAT, HO2S, PCM (25-10)

Ford 5.8L California engine controls wiring diagram page 25-10, IAT sensor and heated oxygen sensor

‹ ›

Wiring diagram of 5.8L California engine controls showing intake air temperature sensor, data link connector, and heated oxygen sensor circuits.

AI caption June 2019 · Photo 384 of 386

This is page 25-10 of a Ford factory-style wiring diagram covering Engine Controls for the 5.8L (351) engine with California emissions. The diagram shows the circuits for the Intake Air Temperature (IAT) sensor, the Data Link Connector (DLC), and the right-hand Heated Oxygen Sensor (HO2S) as they connect to the Powertrain Control Module (PCM). A callout explains that the IAT sensor is a thermistor that decreases resistance as intake air temperature increases, and that the PCM uses the voltage drop to calculate idle fuel delivery, spark timing and EGR control. Another callout explains the HO2S provides a voltage related to exhaust oxygen content for air/fuel ratio regulation. Power for the HO2S heater comes from a 15A fuse (position E) in the engine compartment fuse box, hot in run, on circuit 298 P/O (12V in RUN). Key circuits include 359 GY/R (signal return/reference), 743 GY (IAT signal to PCM pin 25), 351 BR/W (to PCM pin 26), 74 GY/LB (HO2S signal to PCM pin 44), and 57 BK to ground G101 via splice S100. Connectors shown include C101, C103, C107, C164, C185, C198F, and C1025. Cross-references point to page 25-11, Power Distribution page 13-4, and Grounds page 10-2.

Is this accurate? Sign in to help verify it.

Frequently asked questions

What does the Intake Air Temperature (IAT) sensor do according to this diagram?: It is a thermistor that decreases resistance as intake air temperature increases. The PCM uses the voltage drops to calculate idle fuel delivery, spark timing and EGR control.
Which fuse powers the RH heated oxygen sensor on the 5.8L California engine?: Fuse E, a 15A fuse in the engine compartment fuse box, hot in run (see Power Distribution page 13-4), on circuit 298 P/O with 12V in RUN.
What wire colors and PCM pins are used for the IAT sensor?: The IAT sensor uses circuit 743 GY to PCM pin 25 and circuit 359 GY/R (signal return) that also goes to PCM pin 46.
How is the RH heated oxygen sensor (HO2S) grounded?: Through circuit 57 BK, via splice S100, to ground G101 (see Grounds page 10-2).
What circuit carries the HO2S signal to the PCM?: Circuit 74 GY/LB runs from the HO2S through connectors C107F/C107M to PCM pin 44.