B3638 Smart Fortwo I Diagnostic Trouble Code

B3638 Smart Fortwo I code definition:
B3638 is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code for Smart Fortwo I.

B3638 Smart Fortwo I is described as Intake Air Temperature (IAT) Circuit Malfunction. It's actually a general trouble code for a problem on IAT electrical circuit sensor, as it sends incorrect voltage input signals to the PCM. If the car doesn't start, they will proceed by testing the voltage at the fuel pump connector and see if the fuel pump relay, fuse, and PCM circuitry should be inspected.

Symptoms

Symptoms of a B3638 Smart Fortwo I diagnostic trouble code may include:

Blown fuse (if applicable)
Engine surge
Reduction in engine performance, especially at low RPM levels
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :

Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)
Dirty air cleaner element Damaged DPF

Common Misdiagnoses

Vehicle Speed Output Circuit Problem
Cruise Control Servo Indicates Low Problem
A/C System High Pressure High Temperature Problem
PCM Stack Overrun Problem
Transmission Control Module Reprogrammable Memory Problem

Repair Processes :

If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition. Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. If you find a related TSB, the information will often help in diagnosing the code in question as TSBs are crested from many thousands of repairs.

Process Tips

Diagnostic trouble code B3638 Smart Fortwo I is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before B3638 Smart Fortwo I.

Fortunately, B3638 Smart Fortwo I is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.