Renault Megane Quiz
Engine and peripherals

Tests

In this manual: Engine and peripherals
Engine and peripherals — 141Chassis — 79Chassis — 72Renault Mégane III Driver's Manual — 87Electrical equipment — 221Engine and peripherals — 47Electrical equipment — 80Transmission — 14Air conditioning — 30Bodywork — 115Trim and upholstery — 44General vehicle information — 27Air conditioning — 59General vehicle information — 16Transmission — 38Sealing and soundproofing — 7General vehicle information — 3
8steps
~48min
2/5difficulty
Done 0 of 8

INSTRUCTIONS

Only consult the tests when working through a fault tree (ALP) or fault code interpretation.

Certain specific checks are grouped into "tests" and are used as required in various fault trees or fault code interpretations.

TEST 1: Low-pressure circuit check.
TEST 2: Electrical circuit check.
TEST 3: Injector check.
TEST 4: Parameter check.
TEST 5: Intake circuit check.
TEST 6: ECU check.
TEST 7: High-pressure pump check.
TEST 8: High-pressure circuit leak check.
TEST 9: Injector leak check.
TEST 10: Injector return flow during start-up phase.

TEST 1 Low-pressure circuit check
Contrôle du circuit basse pression
Contrôle du circuit basse pression
TEST 2 Electrical circuit check
Contrôle du circuit électrique
TEST 3 Injector check
Contrôle des injecteurs
Contrôle des injecteurs
TEST 4 Parameter check
Contrôle des paramètres
TEST 5 Intake circuit check
Contrôle du circuit d'admission
TEST 6 ECU check
Contrôle du calculateur
TEST 7 High-pressure pump check

INSTRUCTIONS

Special notes: Certain faults will prevent this test from being carried out; deal with them first.

IMPORTANT: It is pointless and dangerous to operate the starter motor for more than 5 seconds.

Contrôle de la pompe haute pression
TEST 8 High-pressure circuit leak check

INSTRUCTIONS

Special note: Certain faults will prevent this test from being carried out; deal with them first.

A command is available that performs a leak test of the engine high-pressure circuit with the engine running.

This command diagnoses a leak in the high-pressure circuit if a fitting is incorrectly fitted or tightened, but cannot detect a small leak if a fitting is not tightened to torque.

This command is only possible if the engine temperature is above 60 °C.

Use command AC029 "high-pressure circuit leak test": the engine will automatically perform a cycle of four accelerations to raise the pressure in the rail; check the high-pressure circuit for leaks.

Take care with any objects (tools or other items) located on the sides of the engine compartment during the four accelerations (possible vibrations).

TEST 9 Injector leak check

INSTRUCTIONS

Special note: Certain faults will prevent this test from being carried out; deal with them first.

Command AC029 also allows the return volume of each injector to be checked in order to detect an internal leak in the injectors.

Required tools:

  • Be sure to use four transparent hoses with an internal diameter of 4 mm and a length of approximately 50 cm.
  • Four graduated measuring cylinders.

PROCEDURE:

  • Make sure the engine coolant temperature is above 60 °C.
  • Switch off the ignition.
  • Disconnect the return hoses from the four injectors.
  • Fit a plug on the pump venturi nozzle to prevent the low-pressure circuit from losing prime.
  • Connect four clear hoses, 4 mm inside diameter and 50 cm long, in place of the injector return hoses.
  • Place the ends of these four hoses into four graduated measuring cylinders.

Once preparation is complete, start the engine and let it run for 2 minutes at idle.

  • Activate command AC029 “high-pressure circuit leak test”. The engine will automatically perform four accelerations to build pressure in the rail and measure the injectors’ internal leakage under these conditions.
  • Once the cycle is complete, activate AC029 a second time to obtain a correct reading of the return volume for each injector.

    At the end of both cycles, the return volume of each injector must be 35 ml maximum. If the return volume of any injector exceeds 35 ml, replace the faulty injector.

  • Disconnect the four clear hoses and reconnect the injector return circuit.

    Watch out for any objects (tools or other) on the sides of the engine block during the four accelerations (possible vibration).

TEST 10 Injector return flow during cranking

INSTRUCTIONS

Special notes: Some faults will prevent this test from being carried out. Deal with them first.

IMPORTANT: It is pointless and dangerous to operate the starter motor for more than 5 seconds.

If the engine does not start, only static leakage can be measured, i.e. leakage from a closed, non-actuated injector subjected to high pressure.

Check that the starting circuit is working correctly (minimum speed of 200 rpm).

Required tools:

  • Four clear hoses with an inside diameter of 4 mm and a length of approximately 50 cm must be used.
  • A test adapter (IMV TEST).

PROCEDURE:

  1. Switch off the ignition.
  2. Disconnect the four injector return hoses from the injectors.
  3. Fit a plug on the pump venturi nozzle to prevent the low-pressure circuit from losing prime.
  4. Connect the four clear hoses, 4 mm inside diameter and approximately 50 cm long.
  5. Disconnect the low-pressure actuator on the pump (IMV brown connector) and connect the test adapter (IMV TEST).
  6. Electrically disconnect the four injectors.
  7. Switch the ignition on, apply the brake and press the “START” button. The starter will cut out automatically after 5 seconds.
  8. Measure the quantity of diesel in each hose.

Replace the injector(s) whose leakage return exceeds 10 cm.

Disconnect the four clear hoses and reconnect the injector return circuit.

Disconnect the IMV TEST and reconnect the low-pressure actuator connector on the pump.

Test yourself

A quick Renault Megane quiz: every answer comes with an explanation and a link to the manual page.