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1. Diesel Clean Advanced Technology (TOYOTA D-CAT) comprehensively regulates engine control (consists of a catalytic system and a fuel injection system) that purifies both particulate matter (PM) and nitrogen oxides (NOx) discharged by diesel engines. The catalytic system purifies hydrocarbons (HC) and carbon monoxides (CO), and reduces PM and NOx with a catalytic converter with the Diesel Particulate-NOx Reduction system (DPNR). The fuel injection system adds fuel into the exhaust port using the exhaust fuel addition injector to produce a RICH state for NOx reduction and maintain a proper catalyst temperature for DPNR catalyst regeneration.
   

   
   
   
   

2. TOYOTA D-CAT components:
   
   

   Component	Description
   DPNR catalytic converter	Reduces HC, CO, PM and NOx.
   Exhaust fuel addition injector	Adds fuel into the exhaust port in order to produce RICH air-fuel ratio for NOx reduction. Also, raises catalyst temperature for DPNR catalyst regeneration.
   Exhaust gas temperature sensor	Used for estimating DPNR catalytic converter temperature and adjusting fuel addition by ECM while DPNR catalyst regeneration is performed. Also, detects DPNR catalytic converter temperature to prevent the catalytic converter temperature from rising too high.
   Differential pressure sensor	Detects the volume of PM deposits and incorrect vacuum hose arrangement on the DPNR catalytic converter.
   Air fuel ratio sensor	Used for controlling air fuel ratio. By controlling the air fuel ratio, combustion control for low temperature combustion and DPNR catalyst regeneration are properly regulated.

3. Diagnostics Trouble Codes (DTCs) table for TOYOTA D-CAT:
   

   УКАЗАНИЕ:

   This table indicates typical DTC combinations for each malfunction occurrence.

   
   

   Trouble Area	Malfunction	DTC No.
   DPNR catalytic converter	Deteriorated or clogged	P2002, P1601, P1386*
   Exhaust fuel addition injector	Stuck open	P1386
   	Stuck closed	P1386, P2002*
   	Low fuel addition volume	P1386, P2002*
   	Open in exhaust fuel addition injector circuit	P1386, P2047, P2002*
   	Short in exhaust fuel addition injector circuit	P1386, P2047
   	Open or short in exhaust fuel addition injector	P1386, P2047, P2002*
   Exhaust gas temperature sensor	Open in exhaust gas temperature sensor circuit	P0544, P0545, P0546, P1386, P2031, P2032, P2033
   	Short in exhaust gas temperature sensor circuit	P0544, P0545, P0546, P1386*, P2002*, P2031, P2032, P2033
   	Exhaust gas temperature sensor	P0544, P0545, P0546, P1386*, P2031, P2032, P2033
   Differential pressure sensor	Open in differential pressure sensor circuit	P1425, P1427, P1428, P2002*
   	Short in differential pressure sensor circuit	P1425, P1427, P1428, P2002*
   	Differential pressure sensor	P1425, P1427, P1428, P2002*
   	Differential pressure sensor clogged	P1426, P2002*
   	Incorrect vacuum hose arrangement of the differential pressure sensor	P1426, P2002*
   Air fuel ratio sensor	Open or short in air fuel ratio sensor or heater circuit	P0031, P0032, P1386*, P2238, P2239, P2252, P2253
   	Air fuel ratio sensor	P0031, P0032, P1386*, P2238, P2239, P2252, P2253
   Exhaust gas leaks	Exhaust gas leaks	P1386*, P2002*
   Fuel leaks	Fuel leaks in fuel addition injector	P1386*
   Supply pump	Correct fuel pressure cannot be fed to the exhaust fuel addition injector	P1386*

   *: There may be no DTC output depending on the condition of the malfunction.
   

4. Diagnostics trouble code description for TOYOTA D-CAT:
   
   

   DTC No.	Description
   P0031	Open or short in air fuel ratio sensor heater control circuit (Low output)
   P0032	Open or short in air fuel ratio sensor heater control circuit (High output)
   P0544	Open or short in exhaust gas temperature sensor circuit (Upstream)
   P0545	Open or short in exhaust gas temperature sensor circuit (Upstream) (Low output)
   P0546	Open or short in exhaust gas temperature sensor circuit (Upstream) (High output)
   P1386	DPNR fuel addition system malfunction
   P1425	Open or short in differential pressure sensor circuit
   P1426	Differential pressure sensor is clogged or has incorrect vacuum hose arrangement
   P1427	Open or short in differential pressure sensor circuit (Low output)
   P1428	Open or short in differential pressure sensor circuit (High output)
   P2002	DPNR catalytic converter malfunction
   P2031	Open or short in exhaust gas temperature sensor circuit (Downstream)
   P2032	Open or short in exhaust gas temperature sensor circuit (Downstream) (Low output)
   P2033	Open or short in exhaust gas temperature sensor circuit (Downstream) (High output)
   P2047	Open in exhaust fuel addition injector circuit
   P2048	Open in exhaust fuel addition injector circuit
   P2049	Open in exhaust fuel addition injector circuit
   P2238	Open or short in air fuel ratio sensor circuit (Low output)
   P2239	Open or short in air fuel ratio sensor circuit (High output)
   P2252	Open or short in air fuel ratio sensor circuit (Low output)
   P2253	Open or short in air fuel ratio sensor circuit (High output)

1. Common rail system:
   The common rail system uses high-pressure fuel for improved fuel economy. This system also provides robust engine power, while suppressing engine vibration and noise.
   This system stores fuel in the common rail, which has been pressurized and supplied by the supply pump. By storing fuel at high-pressure, the common rail system can provide fuel at stable fuel injection pressures, regardless of engine speed or engine load.
   The ECM, using the EDU, provides an electric current to the piezo actuator in each injector to regulate the fuel injection timing and volume. The ECM also monitors the internal fuel pressure of the common rail using the fuel pressure sensor. The ECM causes the supply pump to supply the fuel necessary to obtain the target fuel pressure.
   In addition, this system uses a piezo actuator inside each injector to open and close the fuel passages. Therefore, both fuel injection time and fuel injection volume can be precisely regulated by the ECM.
   The common rail system allows a two stage fuel injection process. In order to soften combustion shock, this system performs "pilot-injection" prior to the main fuel injection. This helps to reduce engine vibration and noise.
   

   
   
   
   

2. Common rail system components:
   
   

   Component	Description
   Common rail	Stores high-pressure fuel produced by supply pump
   Supply pump	Operated by crankshaft Supplies high-pressure fuel to common rail
   Injector	Injects fuel to combustion chamber based on signals from ECM
   Fuel pressure sensor	Monitors internal fuel pressure of common rail and sends signals to ECM
   Pressure Discharge Valve	Based on signals from the ECM, opens valve when sudden deceleration has occurred, or when the ignition switch is off to prevent the fuel pressure from becoming too high
   Suction control valve	Based on signals from ECM, adjusts fuel volume supplied to common rail and regulates internal fuel pressure
   Check valve	Keeps pressure that discharges from injector

3. Diagnostic trouble codes (DTCs) table for the common rail system
   

   УКАЗАНИЕ:

   This table indicates typical DTC combinations for each malfunction occurrence.

   
   

   Trouble Area	Malfunction	DTC No.
   Injector	Open or short in injector circuit	P0200, P1238, P0093*
   	Stuck open	P0093, P1238
   	Stuck closed	P1238
   Fuel pressure sensor	Open or short in fuel pressure sensor circuit or pressure sensor output fixed	P0087, P0190, P0191, P0192, P0193
   Pressure discharge valve	Open or short in pressure discharge valve circuit	P1271, P1272, P0088*, P0093*, P1229*
   	Stuck open	P0093
   	Stuck closed	P1272, P0088*
   Suction control valve	Open or short in suction control valve circuit	P0627, P1229, P0088*
   	Stuck open	P1229, P0088*
   EDU	Faulty EDU	P0093*, P0200*, P1238*, P1271*, P1272*
   Common rail system (Fuel system)	Fuel leaks in high-pressure area	P0093

   *: There may be no DTC output depending on the condition of the malfunction.
   

4. Diagnostic trouble code description for the common rail system:
   
   

   DTC No.	Description
   P0087	Fuel pressure sensor output does not change
   P0088	Internal fuel pressure too high (200 MPa [2039 kgf/cm2, 29007 psi] or more)
   P0093	Fuel leaks in high-pressure areas
   P0190	Open or short in fuel pressure sensor circuit (output voltage is too low or too high)
   P0191	Fuel pressure sensor faulty
   P0192	Open or short in fuel pressure sensor circuit (output voltage is too low)
   P0193	Open or short in fuel pressure sensor circuit (output voltage is too high)
   P0200	Open or short in EDU or injector circuit
   P0627	Open or short in suction control valve circuit
   P1229	Fuel over-feed

УКАЗАНИЕ:

The ECM controls the suction control valve operation to regulate the fuel volume that is produced by the supply pump for the common rail. This control is performed to regulate the internal fuel pressure of the common rail to the targeted injection pressure.

1. Small opening of the suction control valve:
   
   

   1. When the opening of the suction control valve is small, the volume of supplied fuel is small. "A"
      

   2. The suction volume becomes small due to the narrow path despite the plunger stroke being full. The difference between the geometrical volume and suction volume creates a vacuum. "B"
      

   
   
   

   3. Pump output will start when the fuel pressure at (A) becomes higher than the common rail pressure (B). "C"
      

      
      
      
      





2. Large opening of the suction control valve:
   
   

   1. When the opening of the suction control valve is large, the volume of supplied fuel is increased. "A"
      

   2. If the plunger stroke is full, the suction volume becomes large because of the wide path. "B"
      

   
   
   

   3. Pump output will start when the fuel pressure at (A) becomes higher than the common rail pressure (B). "C"