Mihanicos

Very likely the 12v battery voltage has fallen below 11v. Check it with a voltmeter. If you connect the techstream or another good diagnostic tool you should see the 12v battery voltage recorded. Look at the " freeze frame ", there you will find the sequence of events prior to the display of any codes. Chris.

If there is one it is at the highest point of the cooling system, that is where air always goes. Look for it near the radiator, hoses theteto or connecting pipes at the top. Alternatively you can keep the radiator cap off and the air will go out from there. Keep the water level low enough to avoid water overflowing from the radiator. You may need to rev the engine a bit to see the water circulating. Chris.

You have air trapped in the system. Remove the radiator caps and run the engine. When the engine thermostat opens, and the heater on full, sqeeze the heater hoses one at a time while watching the water level in the radiator. When all the air is expelled from the heater of the heat exchanger, the water level in the radiator will rise every time you squeeze a heater hose. Fill with coolant to the maximum level of the expansion tank and put both caps on. Bleed the system from the bleeder screw if your car has one. The only explanation of the steam I can think of is a leak from the heater heat exchanger due to the high pressure of the air and coolant within, probably from the hose connections to the heat exchanger. When there is air in the system, the water flow is not sreamline but turbulant and it may even stop circulating if air is trapped at the water pump, thereby causing engine overheating which in turn produces steam in the circuit and high pressure. Depending where the air is trapped, the tempetature gauge will indicate a false reading but you will be able to see it move up and down indicating water intermittent contacting it. As to a vent failing to discharge hot air, it may stack or a linkage failed or a servo motor malfunction. Hope to have been of some help. Chris.

Have a look at Youtube " how to pass an mot without cat" . There is somebody who did it on Saab V6 using a kit. Apparently there is a very simple modification that will do the trick. Chris.

The solar sensor for both driver's and passeger's sides is located at the centre of the dashboard very close to the windscreen. You can see it protruting above the dashboard, like a ball about 1.5 cm diameter. It measures the amout of sunlight and the airconditioning output is adjusted accordingly. This feature comes into operation when you select auto function for air conditioning. Using an incandescent lamp very close to it from outside the windscreen the techstream will show the sensor's output as you vary the distance of the lamp from the sensor. There are tests you can do to determine the fault and repair it. Chris

Try a professional who only does alignment and uses equipment with spirit levels to measure camber and caster and tow in/out on a board for each wheel. (Car rolls on the board ) The equipment fitted on each wheel for alignment must be set to absolute vertical and horizontal otherwise anything off vertical and horizontal will be included in the wheel adjustment. Having done that initial setting, the front wheels are turned 20 degrees on either direction. At this point the camber and caster are adjusted to specifications. Tow in/out is the last to adjust. A small range of tolerance is given for each parameter. A true experienced professional uses this to compensate the geometry for better road holding, tyre wear etc. I had wheel alignment at the dealer of my previous car, not a Lexus but a german car, and it was going like boat after that. I had to go to a professional like I described to put it right. Chris.

Given that all suspension components and members are in a good condition without any play and that all tyres are of the same make and type, the car should hold the road and not be affected by side winds. A heavy car like the one in question should go straight ahead without holding the steering wheel for about half a kilometer, assuming a level surface and no strong side winds. The wheel geometry is the key to road holding. The modern electronic alignment equipment needs calibration so the set values correspond to the actual true values of the various parameters. There is non electronic equipment that uses absolute methods of measurement that are not subject to wear or adjustment. When an alignment is done using this equipment, the car goes like a train and the slightest command from the steering wheel, the car obeys precisely. The person who is doing the wheel alignment must know what he is doing and what every adjustment does and which way it influences the behaviour of the car. Looking at the wear of the tyres, he will know the cause and he will compensate within the range given by the manufacturer. Sadly there are very few of them left nowadays. Chris.

C1241 refers to battery voltage too high or too low. B1421 solar sensor passenger side. B1424 solar sensor driver side. B2620 refers to ECU power source malfunction. B2421 refers to communications interruption. From the foregoing, you may have a bad 12v battery. The lowest acceptable value is 11v. From the techstream display, the 12v battery voltage had fallen below the minimum threshhold. Whenever this happens, you get all kinds of non related codes. The freeze frame should normally give you the sequence of events leading to each code. Chris.

Reset the mpg function before a trip and the computer will relearn the correct air to fuel ratio resulting to the previous mpg reading. Chris

If you log into lexustech.eu and look up the maintenance schedule of each model, you will see that all " sealed transmissions " have a recommended time/mileage for fluid replacement, depending on use. An australian auto expert John Cadogan, states in one ofhis videos on Youtube that the automatic transmission fluid's properties deganerate by the amout of excess temperature above rated. If I remember correctly, he recommends a fluid change every about 30 000 miles. I saw in a lexus 450h 2015 manual that the transmission should be replaced every 45000 miles and that was a uk car. Chris.

Upon further consideration, without the engine runnining, turn the steering wheel fully to the right and then to the left. If no noise is heard, then the problem is with the power steering. If the noise is present, check all ball joints of the front suspension associated with each wheel. Also check the shock absorber top bearing in the engine bay if rotated by the shock absorber. Chris.

Check the earth connection to the non functioning items. Disconnect both battery terminals and check the ground ( negative cable ) resistance to the non functioning items. It should be very low and not higher than 1 Ohm. Chris.

If I may suggest, try replacing the power steering fluid. As far as I can see from the parts diagram there is no fluid filter that may have been blocked. Turn the steering wheel fully to each direction to bleed the system. My respect and admiration to your knowledge, contributions and days you have won! Chris.

Before doing any alighnment work you should check all the suspension components and eliminate any play between the members. Similarly for the steering wheel, all ball joints and wheel bearings. Also have the shock absorbers checked. Also check that the tyres are a fairly true circle and their steel belt is good. Chris.

You have bought a very reliable luxury performance car that will give you many years of trouble free motoring. It only needs scheduled maintenance which you will find in the repair manual. The repair manual advertised now on ebay uk from usa is the same with the original manual from Lexus for GS European specifications and it is about £50. For the traction battery you can replace any cell or you can buy a replacement original reconditioned battery or a new one from uk. Already other learned members have mentioned a member source. You seem to have had enough repair experience already and we all help each other in any way we can. Some members, you will find, are gurus in mechanical, electrical and electronic engineering. Chris.

Try removing the connectors to the affected circuits, clean them with contact cleaner and reconnect. Contact resistance often develops o er time on low voltage circuits. Usually if you remove the connectors and reconnect, the frction between the individual contacts will do the trick. A circuit diagram is very useful in locating the fault. Try finding the fault with the existing conditions. This way you will get to root of the problem. Chris.

You may have a faulty top dead centre sensor. Chris.

A scientific reply with excellent command of physics!

Try jp-carparts.com and megazip.com. Both specialise in original or OEM parts. Megazip have a big warehouse in UAE and in other parts of the world for quick shipping. With the VIN number of the car and the car model, this information is on the vehicle's identification tag found on the passenger centre pillar, you will find in their website, the manufacturer's drawings with the original part number of the parts you need. Chris.

Thouroughly clean the calipers where the springs fit, the springs, the metal frame of the brakes and the antisqueal pads. Separate each pair on each brake pad and clean them too. If the rear brakes have a single piston, remove and clean the slide pin too. Reassemble using copper grease on the springs, brake pads, antisqueal pads between them and the brake pad. In the slide pin, use silicon grease. Make certain that copper grease never contacts any rubber parts ( piston dust seals, sliding pin dust seals etc) because it will cause them to swell. Replacement rotors usually are not machined to a perfect finish, thereby causing a slight vibration felt at the brake petal when braking lightly but disappearing when braking heavierly. This will disappear as they wear due to braking. This vibration may also contribute to some squealing. This is temporary too. Chris.

Remove the valve covers and spark plugs of each v side and turn the engine by hand from the crankshaft pulley. Inspect the moving parts for correct operation and any damage, timing chains, their tensioner and that all pistons move. In uk you should be able to get anything new or used. Megazip and Jp spare parts, both in Japan, specialise in OEM Lexus spare parts. Chris.

The noise from the engine could be due wrong type of engine oil used, paricurarly wrong viscosity. It could also be due to worn valve buckets and also very unlikely, due to worn valve guides. You may also have low oil level. I always use 98 octane unleaded, it gives a cleaner combustion and the throttle body is always clean. It should prolong the catalyst life as well, hopefully. Chris.

Normally there is a check valve in the discharge side of the fuel pump within the fuel tank which maintains the fuel pressure after the engine is switched off. You can check its function by inserting a pressure gauge. If the fuel pressure is lost after switch off, you can just insert a check valve in place of the pressure gauge. This way you do not need to replace the fuel feed pump to the high pressure pump feeding the injectors. Chris.

Check that the catalytic converter is not blocked. Check the fuel pump delivery pressure to the high pressure pump feeding the injectors. Check the fuel pressure before the injectors. Check that the fuel injectors are not blocked and for correct fuel atomisation and spray pattern. You need a specialist do that. Try fuel injection cleaning chemicals to clean the injectors and the fuel system. Inspect the inlet valves for carbon build up. If you have a direct injection engine, this may be another cause of engine power loss. Always begin with the easy items to check and the least costly. Chris.