C0166 Daihatsu U4b Diagnostic Trouble Code

C0166 Daihatsu U4b code definition:
C0166 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code for Daihatsu U4b.

C0166 Daihatsu U4b is a DTC or a diagnostic trouble code. It is a check engine light code which indicates that the catalyst's system efficiency is less than the required threshold. In simple terms, it means that more pollution is added into the air than what was supposed to be because of your car. Other symptoms that may indicate this problem are when the Check Engine Light illuminates and when there is a visible lack of engine power.

Symptoms

Symptoms of a C0166 Daihatsu U4b diagnostic trouble code may include:

Vacuum leak on the engine
Reduction in engine performance, especially at low RPM levels
Engine surge
Poor acceleration

Possible Causes :

Rusty exhaust systems, cracked exhaust manifolds or damaged or missing gaskets or donuts will cause air leaks.
An air leak forward of the DPF will change the sensor readings resulting in the code
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)

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. Pack the connector cavity with dielectric silicone compound (same stuff they use for light bulb sockets and spark plug wires) and reassemble. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code C0166 Daihatsu U4b 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 C0166 Daihatsu U4b.

Fortunately, C0166 Daihatsu U4b is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.