Fault location tree
| ALP 1 | No communication with the ECU |
INSTRUCTIONS
Nothing to report.
Try the diagnostic tool on another vehicle in perfect working order.Check that the green LED on the interface lights up.
If you cannot communicate with the second vehicle, carry out the "CLIP diagnostic tool check" section.
If you communicate with the second vehicle, carry out the "Vehicle check" section.
| CLIP DIAGNOSTIC TOOL CHECK | Check the cleanliness and condition of the contacts of the diagnostic plug that connects to the vehicle. Check the condition of the cable from the diagnostic socket to the interface, and the cleanliness and condition of the connectors. Check the interface connector. Check the condition of the cable from the interface to the "CLIP", and the condition and cleanliness of the connectors. Check the cleanliness and condition of the "CLIP" socket. If the problem persists, contact the Techline. |
| VEHICLE CHECK | Check the battery voltage. Check the condition and cleanliness of the battery terminals. Check the condition and tightness of the cable from the battery + terminal to the Protection and Switching Unit. Check the condition of the battery earth cable and the good electrical connection to the bodywork. |
| Check the cleanliness and good connection to the bodywork of the injection ECU earth terminal. | |
| Check the 30 A main supply fuse of the Protection and Switching Unit, and the condition and cleanliness of its contacts (see the Protection and Switching Unit diagnosis). | |
| Check the 5 A after-ignition supply fuse of the injection ECU, and the condition and cleanliness of its contacts. (Continued on next page.) |
|
| Take the "Universal breakout box" and check the following pins on the vehicle diagnostic socket (see the diagram in the "Help" section): Pin 1 → + After ignition |
|
| Disconnect the battery and the injection ECU. Check the cleanliness and condition of the ECU connector. Take the "Universal terminal block" and check the continuity of the "CAN" communication lines:Injection ECU track A4, connector A → Vehicle diagnostic socket track 6 |
|
| Check the continuity of the "K" communication line: Injection ECU track B4, connector A → Vehicle diagnostic socket track 7 |
|
| Disconnect the ECU earth terminal from the negative battery terminal. Check the continuity and insulation of the following tracks: Injection ECU track L1, connector C → Earth terminal |
|
| Disconnect the connector marked "PEM" in the Protection and Switching Unit and check that the connector and its terminals are clean and in good condition. Take the "Universal terminal block". Check the insulation and continuity of the following link: ECU track D4, connector B → Protection and Switching Unit connector PEM track 2 (See the connector track number in the corresponding wiring diagram.) |
|
| Disconnect the connector marked "PPM1" in the Protection and Switching Unit and check that the connector and its terminals are clean and in good condition. Take the "Universal terminal block". Check the continuity of the following link: ECU pin M2, connector B → Protection and Switching Unit connector PPM1 pin 1 |
|
| Disconnect the connector marked "PEH" in the Protection and Switching Unit and check that the connector and its terminals are clean and in good condition. Take the "Universal terminal block". Check the continuity of the following link: ECU track D1, connector A → Protection and Switching Unit connector PEH track 1 |
|
| If the problem persists, contact Techline. |
AFTER REPAIR
Carry out a check with the diagnostic tool.
| ALP 2 | The engine does not start |
INSTRUCTIONS
Perform ALP 2 after a complete check with the diagnostic tool.
(Use the Repair Manual at the appropriate chapter to carry out certain operations).
IMPORTANT: do not drive the vehicle until you have checked that there are no faults relating to the throttle body.
| If the starter motor does not engage, there may be an immobiliser fault. Carry out a diagnosis of the Passenger Compartment Central Unit. |
| Check the battery condition. Check that the battery terminals are clean, in good condition and tight. Check that the battery earth is properly connected to the bodywork. Check that the positive battery cables are properly connected. |
| Check that the starter motor connections are correct. Check that the starter motor operates correctly (see the Repair Manual at the corresponding chapter). |
| Check the condition and specification of the spark plugs. Check the mounting, cleanliness and condition of the flywheel signal sensor. Check the air gap of the flywheel signal sensor. Check the condition of the flywheel. |
| Check that the air filter is not clogged. Check that the air intake circuit is not obstructed. |
| Check that there is fuel in the tank (fuel gauge faulty). Check that the fuel tank breather is not blocked. Check that the fuel is suitable. Check that there are no leaks in the fuel circuit, from the tank to the injectors. Check that no hose is pinched (especially after dismantling). Check the fuel pressure and flow rate. Check the operation and sealing of the injectors. |
| Check that the exhaust line is not blocked and that the catalytic converter is not clogged. |
| Check the valve timing. |
| Check the engine compressions. |
| Check the hydraulic tappets if there is a camshaft noise. |
AFTER REPAIR
Carry out a check with the diagnostic tool.
| ALP 3 | Idling problems |
INSTRUCTIONS
Perform ALP 3 after a complete check with the diagnostic tool.
(Use the Repair Manual at the appropriate chapter to carry out certain operations).
IMPORTANT: do not drive the vehicle until you have checked that there are no faults relating to the throttle body.
| Check that the oil level is not too high. |
| Check the sealing of the intake line, from the throttle body to the cylinder head. Check that the fuel vapour canister purge is neither disconnected nor stuck open. Check that there are no leaks in the fuel vapour canister purge circuit. Check that there are no leaks in the brake booster circuit. Check that there are no leaks in the oil vapour recovery circuit (manifold - cylinder head). Check that there are no leaks at the manifold pressure sensor. Check that there are no leaks at the air temperature sensor. |
| Check that the air filter is not clogged. Check that the air intake circuit is not obstructed. Check that the throttle body is not dirty or coked up. |
| Check the condition of the pencil ignition coils and the cleanliness of their connectors. Check the electrical resistance of the secondary circuits of the pencil ignition coils. Check the condition and specification of the spark plugs. Check the mounting, cleanliness and condition of the flywheel signal sensor. Check the air gap of the flywheel signal sensor. Check the condition and cleanliness of the flywheel. |
| Check that the fuel tank breather is not blocked. Check that the fuel is suitable. Check that there are no leaks in the fuel circuit, from the tank to the injectors. Check that no hose is pinched (especially after dismantling). Check the fuel pressure and flow rate. Check the operation of the injectors. |
| Check that the exhaust line is not blocked and that the catalytic converter is not clogged. |
| Check the valve timing. |
| Check the engine compressions. |
| Check the hydraulic tappets if there is a camshaft noise. |
AFTER REPAIR
Carry out a check with the diagnostic tool.
| ALP 4 | Driving problems |
INSTRUCTIONS
Perform ALP 4 after a complete check with the diagnostic tool.
(Use the Repair Manual at the appropriate chapter to carry out certain operations).
IMPORTANT: do not drive the vehicle until you have checked that there are no faults relating to the throttle body.
| Check that the oil level is not too high. |
| Check the condition of the pencil ignition coils and the cleanliness of their connectors. Check the electrical resistance of the secondary circuits of the pencil ignition coils. Check the condition and specification of the spark plugs. Check the mounting, cleanliness and condition of the flywheel signal sensor. Check the air gap of the flywheel signal sensor. Check the condition and cleanliness of the flywheel. |
| Check that the air filter is not clogged. Check that the air intake circuit is not obstructed. Check that the throttle body is not dirty or coked up. Check the sealing of the intake line, from the throttle body to the cylinder head. |
| Check that the fuel vapour canister purge is neither disconnected nor stuck open. Check that there are no leaks in the fuel vapour canister purge circuit. Check that there are no leaks in the brake booster circuit. Check that there are no leaks in the oil vapour recovery circuit (manifold - cylinder head). Check that there are no leaks at the manifold pressure sensor. Check that there are no leaks at the air temperature sensor. |
| Check that the fuel tank breather is not blocked. Check that the fuel is suitable. Check that there are no leaks in the fuel circuit, from the tank to the injectors. Check that no hose is pinched (especially after dismantling). Check the fuel pressure and flow rate. Check the operation of the injectors. |
| Check that the exhaust line is not blocked and that the catalytic converter is not clogged. |
| Check the valve timing. |
| Check the engine compressions. |
| Check the hydraulic tappets if there is a camshaft noise. |
AFTER REPAIR
Carry out a check with the diagnostic tool.
AFTER REPAIR
Carry out a check with the diagnostic tool.
Test yourself
A quick Renault Megane quiz: every answer comes with an explanation and a link to the manual page.