23 · Diagnostics

P0238 - turbo pressure

Make: Alfa Romeo
Model: Brera and Spider Factory Service Manual
Year: 2005–2010
Section: Examiner - diesel electronic management › P0238 - turbo pressure

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Fault diagnosisP0238 - turbo pressure

P0238 - TURBO PRESSURE

2.4 JTD 20v

The diagnostic equipment signals: Error P0237 (Turbo pressure)

This error is detected if the difference between the actual distribution line oil pressure and the nominal pressure is more than 250 bar for at least 2 secs.

0	PRELIMINARY CHECKS	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the engine oil level is correct Op. 0010T11 ENGINE OIL - CHECK LEVEL AND TOP UP, IF NECESSARY Check that the air intake/vacuum circuit is working properly by carrying out the See Test 1048OA AIR INTAKE/VACUUM CIRCUIT CHECK Check the condition of the fuel supply circuit and make sure that it is working properly carrying out the See Test 1040OA FUEL SUPPLY CIRCUIT CHECK Visually inspect the condition of: High pressure fuel pump Injector pipe Fuel pressure sensor on the rail Fuel pressure regulator Fuel shutter solenoid valve Injectors	Move on to Step 1	1. Oil level incorrect	1. Restore the correct engine oil level Op. 0010T11 ENGINE OIL - CHECK LEVEL AND TOP UP, IF NECESSARY
		Move on to Step 1	2. Components visually faulty	2. Repair or, if necessary, replace the faulty components
1	IMA INJECTOR CLASSIFICATION CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the injectors have the correct IMA classification using the diagnostic equipment. If not, carry out the programming and check that the result is positive	Move on to Step 2	The programming is not successful	Replace the engine management control unit Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - .R
2	HIGH PRESSURE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the diesel pressure parameter is correct. See Test 1060OD INSPECTION OF THE HIGH PRESSURE FUEL CIRCUIT	Move on to Step 13	Pressure not correct	Move on to Step 3
3	INJECTOR HIGH PRESSURE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the diesel leaks from the injector recirculation connections are small (seepage) and roughly equal to one another. See Test 1060OC INJECTORS SEAL TEST	Move on to Step 4	Significant leak from one injector	Replace the injector
4	LOW RETURN PRESSURE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the pressure in the return pipe to the tank is less than 1 bar See Test 1060OA CHECK ON RETURN LOW PRESSURE FUEL CIRCUIT	Move on to Step 5	Pressure above the maximum limit: return pipe to the tank obstructed	Repair the pipe, if necessary, replace it
5	LOW SUPPLY PRESSURE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the diesel pressure between the filter and the pressure pump is between 2 and 3 bar See Test 1060OB CHECK ON SUPPLY LOW PRESSURE FUEL CIRCUIT	Move on to Step 11	Pressure below the minimum limit or above the maximum limit	Move on to Step 6
6	LOW SUPPLY PRESSURE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Constrict the return pipe downstream of the valve and carry out the test again See Test 1060OB CHECK ON SUPPLY LOW PRESSURE FUEL CIRCUIT with the pipe constricted checking that the pressure at the filter outlet remains below 2 bar	Move on to Step 7	Pressure rises to 5 bar: pressure regulator valve on filter mounting incorrectly adjusted	Replace the valve Op. 1044B16
7	LOW SUPPLY PRESSURE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the difference in pressure upstream and downstream of the filter is less than 1 bar	Move on to Step 8	Difference in pressure more than 1 bar	Replace the fuel filter cartridge Op. 1044B20
8	LOW SUPPLY PRESSURE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the supply pump pressure at the filter inlet is more than 2.2 bar	Move on to Step 11	Pressure below 2.2 bar	Move on to Step 9
9	LOW SUPPLY PRESSURE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Measure the difference in pressure between the electric pump outlet and the filter inlet and check that it is less than 0.3 bar	Move on to Step 10	Difference in pressure more than 0.3 bar	Replace the pipe
10	LOW SUPPLY PRESSURE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the pump supply voltage is equal to 12V and that the current uptake is between 2 and 10 A See Test 1040AA SUPPLY VOLTAGE AND ABSORPTION CURRENT CHECKS	Move on to Step 11	1. Voltage lower than 12 V	1. Renew electrical wiring See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
			2. Current greater than 10 A: pump defective	2. Replace the fuel pump
			3. Current less than 2 A: pump obstructed	3. Replace the fuel pump and clean the fuel tank
11	CHECK ON CORRECT OPERATION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Replace the DRV high pressure regulation valve and check that the fault is no longer present. Op. 1060E50 PRESSURE REGULATOR ON PRESSURE PUMP - R.R.	End of diagnosis	The fault persists	Move on to Step 12
12	CHECK ON CORRECT OPERATION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Replace the pressure pump and check that the fault is no longer present Op. 1060E10 DIESEL INJECTION PRESSURE PUMP - R.R.	End of diagnosis	The fault persists	Contact the Service Department for further information on the problem
13	PRESSURE REGULATOR REPLACEMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Replace the fuel pressure regulator and check that the problem disappears Op. 1060E50 PRESSURE REGULATOR ON PRESSURE PUMP - R.R.	Move on to Step 14	The fault persists	Renew the pressure regulator and replace the flow valve Op. 1060E20
14	CHECK ON CORRECT OPERATION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Replace the engine management control unit and check that the fault is no longer present Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - .R	End of diagnosis	The fault persists	Contact the Service Department for further information on the problem

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Parts & tools for this job For 2005 Alfa Romeo Brera

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