SECTION 303-14: Electronic Engine Controls
2000 Expedition/Navigator Workshop Manual
DESCRIPTION AND OPERATION
Electronic Engine Controls
The electronic engine controls consist of the:
- powertrain control module (PCM)
- throttle position (TP) sensor
- idle air control (IAC) valve
- engine coolant temperature (ECT) sensor
- camshaft position (CMP) sensor
- crankshaft position (CKP) sensor
- mass air flow (MAF) sensor
- intake air temperature (IAT) sensor
- heated oxygen sensor (HO2S)
- vehicle speed sensor (VSS)
- cylinder head temperature (CHT) sensor
The PCM needs the following inputs to calibrate the engine correctly:
- engine coolant temperature
- amount of engine detonation
- cylinder head temperature
The TP sensor:
- sends the PCM a signal indicating the throttle plate angle.
- is the main input to the PCM from the driver.
The IAC valve:
- controls bypass air around the throttle plate at low speeds.
- is controlled by the PCM.
The ECT sensor:
- sends the PCM a signal indicating engine temperature.
- resistance decreases as coolant temperature increases.
The CMP sensor:
- sends the PCM a signal indicating camshaft position used for fuel synchronization.
The CKP sensor:
- sends the PCM a signal indicating crankshaft position.
- is essential for calculating spark timing
The MAF sensor:
- sends the PCM a signal indicating mass airflow rate of air entering the engine.
The IAT sensor:
- sends the PCM a signal indicating the temperature of the air entering the engine.
- resistance decreases as temperature increases.
- has the ability to create a voltage signal dependent on exhaust oxygen content.
- provides feedback information to the PCM used to calculate fuel delivery.
The 4.6L KS is located in the lifter valley. The 5.4L has a unique linear KS located in the lifter valley.
- The KS sends a signal to the PCM indicating engine detonation.
The CHT sensor:
- is mounted into the wall of the cylinder head and is not connected to any coolant passages.
- sends a signal to the PCM indicating cylinder head temperature.
- If the temperature exceeds 126°C (258°F) 5.4L, 130°C (265°F) 4.6L, the PCM disables four fuel injectors at a time. The PCM will alternate which four fuel injectors are disabled every 32 engine cycles. The four cylinders the are not being fuel injected act as air pumps to aid in cooling the engine.
- If the temperature exceeds 154°C (310°F) 5.4L, 166°C (330°F) 4.6L, the PCM disables all of the fuel injectors until the engine temperature drops below , 154°C (310°F) 5.4L, 153°C (308°F) 4.6L.
- is gear driven by the transmission.
- sends a signal to the PCM indicating vehicle speed. For additional information, refer to Section 307-01A R4100 and/or Section 307-01B 4R70W
P1151 - Lack of HO2S-21 Switch, Sensor Indicates Lean
A HEGO sensor indicating lean at the end of a test is trying to correct for an over-rich condition. The test fails when fuel control system no longer detects switching for a calibrated amount of time.
See Possible Causes for DTC P1130
P1130 - Lack of HO2S-11 Switch, Fuel Trim at Limit
The HEGO Sensor is monitored for switching. The test fails when the HO2S fails to switch due to circuit or fuel at or exceeding a calibrated limit.
- Short to VPWR in harness or HO2S
- Water in harness connector
- Open/Shorted HO2S circuit
- Corrosion or poor mating terminals and wiring
- Damaged HO2S
- Damaged PCM
- Fuel System:
- Excessive fuel pressure
- Leaking/contaminated fuel injectors
- Leaking fuel pressure regulator
- Low fuel pressure or running out of fuel
- Vapor recovery system
- Induction System:
- Air leaks after the MAF
- Vacuum Leaks
- PCV system
- Improperly seated engine oil dipstick
- EGR System:
- Leaking gasket
- Stuck EGR valve
- Leaking diaphragm or EVR
- Base Engine:
- Oil overfill
- Cam timing
- Cylinder compression
- Exhaust leaks before or near the HO2S(s)
A fuel control HO2S PID switching across 0.45 volt from 0.2 to 0.9 volt indicates a normal switching HO2S.
P0153 - HO2S Sensor Circuit Slow Response (HO2S-21)
See DTC P0133
P0133 - HO2S Sensor Circuit Slow Response (HO2S-11)
The HEGO Monitor checks the HO2S Sensor frequency and amplitude. If during testing the frequency and amplitude were to fall below a calibrated limit, the test will fail.
- Contaminated HO2S sensor.
- Exhaust leaks.
- Shorted /open wiring.
- Improper fueling.
- MAF sensor.
- Deteriorating HO2S sensor.
- Inlet air leaks.
Access HO2S test results from the Generic OBD-II menu to verify DTC.