Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Deceleration Mode
During deceleration, the ECU receives inputs from the CTS, MAT, MAP, EGO, speed and knock sensors. It also is informed of throttle, gear (automatic transaxle models) and A/C control position.
When the ECU receives deceleration input from the closed throttle (idle) switch, it grounds the EGR valve/canister purge solenoid. This interrupts vacuum to EGR valve and canister purge function. The injector is grounded, and during rapid deceleration, the ECU may stop injection for a short period of time. The ECU also controls engine idle speed and throttle stop angle.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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