1999 v70 p0270

lalatheram · Post by **lalatheram** » 08 Jun 2014, 15:30

I have a trouble code po270. cly 4 injector circuit, low voltage.it is a 1999 v70xc. any body have any ideas on how to fix this car.i have replace the plug, and replace the injector electric plug.

Post by **abscate** » 09 Jun 2014, 03:35

Pull the number 4 injector plug and check it for corrosion. Trace the wiring back and look for pinched or abraded wires under the spark plug cover.

Faulting an intermittent voltage problem is hard without a voltmeter (DVM) or even a o-scope. The fuel injectors are fired by grounding through the ECM, with constant 12V(to be confirmed) on them, so with a DVZm you could look for 12 volts on one of the ions while up you wiggle wiring.

Wiring is top suspect
Bad fuel injector...test by swapping number 1 and 4 to see if code moves. Buy new injectors seals before you do this in case they crumble on removal
Bad ECM...unlikely, mentioned here as everyone likes to blame the ECM for problems and 99.95% of the time it isn't the ECM

lalatheram · Post by **lalatheram** » 10 Jun 2014, 06:45

thank you i will try doing those test.

lalatheram · Post by **lalatheram** » 14 Jun 2014, 17:39

i have swapped injectors. 1 and 4. i clear the codes and the car runs great. after driving for a couple of miles and shutting it off , the engine lite comes back on and the car runs ruff. same code , p0270. i took a volt meter and checked all the injectors. 4 out 5 have a 8.39 volts and the cyl 4 has 12.08 volts. clear the codes and the 4th cyl has 8.39 volts. any ideas wear to check or what to do.

Post by **Ozark Lee** » 14 Jun 2014, 18:07

The constant battery voltage on number four is indicative of a wiring problem between the injector and the ECU. Sometimes the ECU edge connector can get corroded and cause that type of problem so it is worthwhile to pull the ECU and give the connector a spray with electrical contact cleaner. Beyond that you are looking at a wiring problem or a problem with the number 4 injector connector. If you want to be real cautious disconnect the battery before pulling the ECU.

The wiring problems are always a PITA to find but, once found, they are normally easily repaired.

...Lee

Post by **abscate** » 15 Jun 2014, 05:10

You are getting close. You've already saved ypurself 600 bucks in diagnostics fees!

Hook up the voltmeter to injector 4, measure the 8 volts, and start gently wiggling the wiring working your back to the ECU. Don't go gorilla on the wiring, just bump it while watching for any change in the voltmeter closely. Somewhere, it will start the magical 0-12V dance that will tell you where the break is.

I'll call no ECU fault on this one ( although reseating it per Lee makes sense)....

Post by **precopster** » 15 Jun 2014, 07:55

On '99 Densos they started the need for the special ECM removal tool; not certain about the Bosch ones but very likely.