Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

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Deceleration

PCM MONITORS:

- Engine Temperature (ECT Sensor)
- Manifold Vacuum (MAP Sensor)
- Charge Temperature Sensor
- Cam and Crankshaft Position (CMP and CKP Sensors)
- Throttle Position (TPS)
- Exhaust Gas Oxygen Content (O2S)
- A/C Switch Status
- Battery Voltage
- Engine Knock Sensor

UNDER NORMAL DECELERATION, PCM:

Continues normal (reduced) injection.

De-energizes EGR system, by grounding Electronic EGR Transducer (EET) solenoid.

UNDER HARD DECELERATION, (CLOSED THROTTLE AND ABRUPT INCREASE IN MANIFOLD VACUUM) THE PCM:

Ignores oxygen sensor input, and initiates fuel cut-off strategy, firing injector only once per engine revolution.

Disables EGR system, by grounding EGR solenoid.

Disables EVAP purge system, by grounding EVAP solenoid.