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Matt
Matt, Engineer
Category: Lexus
Satisfied Customers: 21260
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
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ABS light flashing, Trac Light Flashing and CEL on? abs and

Customer Question

ABS light flashing, Trac Light Flashing and CEL on?
JA: Does the light stay on, or does it blink?
Customer: abs and trac light blink, CEL stays on
JA: What is the model/year of your Lexus?
Customer: 2003 IS300
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: scanned error codes, all
JA: Anything else you want the mechanic to know before I connect you?
Customer: P1201, P1271-1278, 1281
Submitted: 7 months ago.
Category: Lexus
Expert:  Matt replied 7 months ago.

hello

OK P1201 is a cylinder1 misfire

p1271 is ambient air temp sensor fault

P1278 is injector fault cylinder 3

p1281 is a general misfire

Its likely that the faulty injector is creating the P1281 code so I'd begin by checking the wiring to the injectors looking for damaged insulation and corroded contacts

I'd also suggest to check for a lack of fuel pressure from the electrical pump at the tank.

1st thing to try is to remove the fuel filler cap and then flick the ignition on whilst listening for the brief ‘buzz’ of the pump

If the connections to the pump are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,

Ideally measure the pressure at the injector rail (should usually be around 3Bar / 45psi +) and if this is low check the pump as described and also consider changing the fuel filter as if this partially blocked this too will reduce pressure.

Customer: replied 7 months ago.
Thank you for your help, however the codes you were given were incorrect the correct codes are C1271-C1278, C1281. My appoligies my kid was reading them off to me
Expert:  Matt replied 7 months ago.

Hello

ok I did wonder as any P code is engine related and your trouble seemed to be more chassis related

so C1278 is a fault with the steering angle sensor

C1281 - Master cylinder pressure sensor output signal is faulty

and C1271 = Low Output Voltage of Right Front Speed Sensor

So I'd 1st suggest to replace the wheel speed sensor as this will have the strongest effect on the system

and I'd also try moving the steering from lock to lock 5 times in a row to calibrate the steering sensor , with the engien running but car stationary

Customer: replied 7 months ago.
Actually it's c1271, 72, 73, 74, 75, 76, 77, 78...... Highly unlikely that all speed sensors went out at once
Expert:  Matt replied 7 months ago.

OK thanks for that

I'd agree to get all the sensor codes at once means its unlikely they have all failed

so its much more likely to be a lack of power to the ABS module / control unit

so I'd 1sts check its fuse has 12V with the ignition on and if it does then I'd consider sending the module for testing / repair

http://www.ecutesting.com/abs_pumps_modules.html