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post #54 of (permalink) Old 24th June 2016
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Re: Renault Clio 1.4 8v - Info on starting problems - HELPFUL!

Here is a summary of two "Clio not starting" threads.

First of all, about the immobilizer light, there are a few different situations.

1. How it normally operates when everything is working:
Immobilizer light blinks at 1 Hz frequency with NO KEY in the ignition lock. You put the key in and turn the key to "ON"-position. The immobilizer light now glows constantly red for a few seconds and then goes out. Turn the key one position more to crank the engine. The immobilizer light stays off and the engine fires up.

2. Immobilizer light is not flashing at all when there is no key in the ignition lock. The UCH is not receiving power or it is faulted.

3. Immobilizer light flashes at 4 Hz (=faster than the normal rate). This is to say that the UCH is not recognizing the key which is inserted into the ignition lock as an authorized key to start the engine. Probably engine will not rotate or will rotate for a couple of times and then stop rotating. Problem with the key fob (dried/cracked/bad/non-conductive soldering joints on the components of the key fob PCB) or the key detector ring around the ignition lock base is, for some weird reason, broken. Or the UCH is broken.

4. Immobilizer light stays lit when trying to crank the engine. This indicates a problem in the data connection between the UCH and the ECU . Probably a corroded/broken wire in the loom connecting the ECU and the UCH , or the UCH itself has an internal fault.

Short legend:
1. UCH = body electrics control module, controls everything except the under-bonnet stuff (the ECU handles the under-bonnet). UCH is located in the passenger compartment under the dashboard, black plastic box with three connectors.
2. wiring loom = just a bunch of wires usually taped together with black tape
3. key fob = the black plastic casing on your car key which conceals inside the key's electronics

Always read the OBD2 fault data first!
Order a cheap OBD2 bluetooth adapter from anywhere online (e.g. ebay or and acquire, for example, the Torque Pro Android software. You can get it from Google Play Store. Install the software and read your OBD2 codes using your Android phone. This costs around 10 euros. Investment which pays back the first time you would need to let a repair shop read the codes for you. These OBD2 adapters usually require pairing with the phone through the bluetooth menu of the phone and the pin code for this is usually 1234 or 0000.
But, do understand that a car specific reader, like the Renault CAN Clip device will extract a lot more fault code data from the car than the OBDII-adapter is capable of.

1. The key fob has a problem.
- The key PCB soldering has gone dry/corroded. (engine turns over a few times and comes to a halt, immo light flashes at 4 Hz when trying to start) try with a spare key, if it makes no difference -> probably not a problem with the keys (unless the spare had already broke earlier).
- Apparently cleaning the original key blade has helped some people. Personally I do not believe in this working at all, but it is possible that the key blade acts as an antenna for the decoder ring located around the ignition lock base. Or then it is just the dried solder joints inside the key.
- Check out this thread to get an idea about what you are looking for if you decide to try to tackle the dry joints yourself. The key is not for a Clio but the principles are the same: Megane II - Keycard repair instructions / development
- There is possibly a chip inside the key which needs to sit in its proper holder. If the key makes a rattling sound when shaken, this chip has gone loose.
- Some people report that changing the key fob battery (type: CR1220) has helped. (Personally, I think the battery should not be even required in the key for the car to start but it might depend on what year your Clio is, maybe the older ones require a battery inside the key fob).
- Not 100 % sure about this, but: Changing the key fob battery will not fix the problem if the engine is cranking over just fine, i.e., the immobilizer light is not blinking at rapid pace (4 Hz) and preventing the engine from cranking.

2. Crankshaft position sensor is broken or just dirty (according to many people who got it working just by cleaning the sensor). Or wiring of the crank position sensor is busted.
- Will not stop the engine from cranking over.
- Check for visual problems on the wiring beginning at the sensor.
- Cleaning: electronics cleaning spray/q tip/scouring pad/soft wire brush. Clean especially the contact pins in the electrical connector.
- Location: at the end of the engine, behind a coolant tube. Kind of a half moon shaped piece of metal with wires going to it. Look through the topic to see pictures of it. It is really easy to replace yourself after you find it.
- Symptoms: Intermittent periods of the car not firing up. Sometimes the engine just shuts off while driving.
- How to diagnose: Remove a spark plug and hold it in the imminent vicinity (1 centimeter or closer) of any metal part of the engine block. Not touching directly the metal though, but in the air! Get someone to crank the engine by turning the key. If a spark jumps from the plug to the metallic engine block, then the crankshaft position sensor (a.k.a. TDC a.k.a. top dead center sensor) is supposedly working.
- When doing the spark plug test, wear rubber gloves or you will feel the spark on your hands. One alternative is to stick a screwdriver into the HT lead and hold the screwdriver near the metallic engine block. The 20 000 volt spark does not require a spark plug attached to the HT lead to jump onto the engine block.

3. Fuses have a bad contact in the engine bay fuse box or in the interior fuse box(located on the side of the dashboard under a small panel).
- Engine bay problems are thousand times more likely, unless your sunleak is leaking water into the dashboard.
- Repairing is done one fuse at a time: Pull out - plug back in - rinse crap away with electronics cleansing spray if deemed necessary.
- Also inspect all fuses that they are not burnt. (That the wire inside the transparent plastic case is not broken)

4. UCH fault (this is one type of an immobiliser fault)
- When giving a little tap to the UCH black computer with a screw driver in the passenger compartment fixes the problem -> definitely an UCH PCB problem. Also, could include the symptom of the fault disappearing after the car has been driven for some time.
- A tell-tale symptopm is a constant clicking/chattering of relays underneath the dashboard. Although, if the battery is totally empty this will also happen.
- More tell-tale symptoms include intermittent irrational operation of some or all of the following: blinkers, wipers, headlights, electric windows, dashboard backlight, interior light, etc.
- If a problem exists, it will present itself more often in the winter temperatures. (for some odd reason) (this has been confirmed from a Renault dealer)
- Another tell-tale symptom is if the car hesitates to lock the doors via remote. Such that the car will flash its blinkers (as a signal that doors have been locked) but the doors will instantly unlock again.
- If there is no red immobilizer light flashing (slow pace, a.k.a., at 1 Hz) with no key in the ignition lock, then the UCH is not receiving power or is otherwise broken.
- If the car is very new, I would not suspect an UCH fault. Maybe when the car is 10+ years of age, then I would start considering an UCH fault.
- When you try to crank the car by turning the key straight to the crank engine position, and the engine will now crank for around 3 seconds and then stops. This would indicate the immobilizer has not received "all system go" and thus it inhibits the starting process. This could indicate a wiring problem in the ECU wires or an electrical fault at the ECU computer or the UCH computer.

5. Black (there are 3 similar black ones) relays inside the engine bay fuse box.
- Switch their locations between each other to troubleshoot if the relays itself are at fault.
- After altering the locations of the relays, try to start the engine and inspect if there is any clear alteration in the behaviour of the immobilizer light, etc.
- Squirt a liberate amount of electronics cleaner to clean the fuse box base from road dirt.
- Visually inspect the wiring near the fuse/relay box for problems.
- It is not uncommon for the relays to fail.
- From username terry nagel's post: Apparently, the first black relay (the one nearest the engine) is the engine control relay. The middle black relay is the starter motor relay. The black relay (nearest the wing) is the engine coolant blower relay. The brown relay is the fuel pump relay (Read this relay information on another site)

6. The engine earth strap has come loose or is corroded and thus broken.
- Located near the gearbox in the engine bay.
- Connects the engine to the chassis of the car.
- A braided cable about 1 inch thick.
- If you can push start the car just fine, this is definitely a possible cause of starting problems as the starter motor power goes through this cable and if it is corroded badly enough, then the starter might not budge!

7. Problem with the starter motor
- The starter motor got stuck / starter carbon brushes are worn out. (Put the car in 3rd gear and rock it back and forth) (smack the starter motor with a hammer -> now starts up just fine -> starter needs to be looked at!)
- The starter motor cables have corroded and are not conducting.
- Detach the starter wires from on top of the starter motor and clean all mating surfaces using a soft wire brush or something similar.
- Re-attach all wiring in correct places.
- Symptom reported by a poster: The car won't start when hot, needs to cool down for 10-20 minutes --> possibly a corroded connection on the starter motor. The heat from the engine thermally expands a nut, under which a cable is attached and the contact is lost until the bolt cools off and regains the pressure onto the connector, or something like that.

8. Problem with the fuel pump
- May be at fault if the car sometimes starts, sometimes does not.
- Push in the red button on the fuel pump, which is a crash activated emergency fuel pump cut-off feature.
- Remove the seat rear seat located in top of the fuel pump and give the pump a good whack -> works now -> fuel pump is faulty.
- Fuel pump earth is the same as the tail light earth. So check the tail light earthing.

9. Random wiring loom fault somewhere (can be impossible to pinpoint exact location)
- The wiring connector underneath the airbox. Wire insulation worn down and the wires short-circuiting to each other.
- Wires between the UCH and ECU are busted.
- A constant red immobilizer light stays on, when you try to crank the car.
- A Renault CLIP device can be utilized to troubleshoot these wiring loom problems, contact a garage who does Renault repairs
- Possibly also wires from battery to ECU are corroded. Check the battery cables that they are secured in place tightly.

10. Engine coolant/temperature sensor is broken.
- Starting problems appear most likely only when the engine is hot.

11. The decoder ring around the ignition lock base
- Very unlikely to get broken if not have been manhandled with a screw driver.

12. Throttle body is dirty
- The idle air control valve is not working properly. Clean it.
- I estimate this to be an unlikely cause for starting problems.

Random stuff people have successfully started their Clio with:

1. Keep the key fob button pressed while turning the key to crank the car. (Someone could explain why this has worked on many occasions...!?)
2. Put on the ignition without cranking, leave key in for 30 seconds, take out key, lock doors, open doors and the car will now fire up when cranked.
3. Quote: "Whilst in ignition, press and hold the button on your key, and whilst holding it, turn it to position one, and back into ignition, and the red light should stay red for a few seconds and then go out. When the red light has stopped flashing and gone out, that is when your clio should start up! "
4. Changing the coil pack. This probably will not fix the problem if the coil fault indication light is not illuminated on the instrument panel. If it is illuminated --> change the ignition coil (s). Read the OBD data first to determine the faulty coil if there are multiple.

Random notes: Lambda sensor fault should not affect the startup of a car in any way. Although it might cause bad idle once the car is running.
MAP sensor fault should not affect the starting of the car, although the car would probably hesitate to take revs when the throttle pedal is pushed.
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