Weres the ground for injector circuit in 1996 2.4 quad 4

DTC P1200 Injector Control Circuit
An incorrect voltage level is being detected on an injector driver circuit. A injector driver is a transistor inside the engine computer , it controls the injector by supplying a ground . ECM Inputs and Outputs Diagnosis Do you know what cylinder ?

If you unplug the injector does it stop dumping fuel? If that is the case the ground circuit is always grounded, if it stills dumps then the injector is stuck open.

if you have a $5 test light, you could find the problem. just know that all eight injectors have a constant voltage applied to them anytime the key is in run or start. and also that 4 of the injectors share a common ground, they have their ground wires spliced together before the ground wire enters the pcm to be internally grounded. and the other four injectors are the same- their ground wires splice together. so your four that don't pulse have lost either the power to them, or the common ground wire for the 4 may have broken. or lost connection.

it is easier to check the power side first, so clip a test light lead to the negative battery post or cable, turn the key to on,and probe each injector connector. one of the terminals at all eight injectors will be the power wire, and it should light up the test light. if all eight injectors have power to them, you know it must be a ground side problem. if you find that 4 injectors have no power to them, look for a broken splice in the power wire to all injectors. back in those days, injectors were "bank fired". one side or bank of the engine all had the injector grounds spliced together, so all injectors on one bank fired (pulsed) simultaneously, and then the other bank was fired or pulsed. that was good until sequential injection matched the pulse to the cylinder ready to fire, more precise, and in the modern systems each injector ground has a separate ground inside the pcm. no more splicing of the ground wires, and having bank fired engines.


when the pcm grounds the circuit, the injector coil is energized and the injector opens to spray fuel out. so the injector has constant voltage to it. only when the circuit is grounded is that power applied across the injector.

Check for a fuse for the injectors in the power distribution box by the battery. Parts stores sell a cheap little tester called a "noid light" for testing injector circuits. They come in several sizes, so get the one that fits your injector connector. To use it, you pull off one injector connector and plug in the test light. If the circuit is good, the light will be blinking when the car is cranked over. If you get nothing, pull off all the injector connectors and test again. If you have one shorted injector, it may have shut down your injector drive circuit- that's why to pull off all connectors and re-test.
Here's a brief on how the injector circuit works: When key is on. the injectors will have constant battery voltage available to them on the power side (the injector drive circuit). When the engine is cranking or running, the engine computer will momentarily ground the ground circuit of injector (the ground wire goes straight into the computer for internal grounding), causing the injector to pulse. If you have no pulsing, determine if it is the drive circuit (no power to injectors), or the ground circuit that has failed.

I wouldn't think CPS if you are getting a good blue healthy spark.
Check your injector circuit with a test light: Pull off one injector connector, ground the test light, and probe the injector connector with key ON. If your injector drive circuit is working, one of the terminals on the injector connector should have a steady light. Now check the injector ground circuit: move the test light lead to the positive battery post, and probe the injector terminal that did not light the test light, while someone cranks the car over. If ground is working, you should have a blinking light, meaning the computer is properly groundind the injector to pulse. If both tests are good, the injector circuit is working properly. The drive circuit is routed through the ignition switch, and the ground circuit goes into the computer.

I will start by pinout check current + to ECM and - ground there is many .
A Quad driver work like a big fuse d?pends some are resettable and other not reset(ECM defect) if it is so then you have to check all solenoid not short to ground before replacing ECM it will burn without checking the solenoid
hope it help

The code 22 is the ect sensor voltage to low( engine coolant temperature sensor input below minimum acceptable voltage) Code 27 injector #4 control circuit ( injector #4 output driver does not respond properly to control signal). Code 43 ignition coil #3 primary circuit (peak primary circuit current not achieved with maximum dwell time. And code 55 completion of fault code display on check engine lamp. Hope this will help you.

CODE 27 - Injector Control Circuit, output driver does not respond properly to the control signal

Code 27 MIL light options: OBDII
P0201 - Injector #1 Control Circuit
P0202 - Injector #2 Control Circuit
P0203 - Injector #3 Control Circuit
P0204 - Injector #4 Control Circuit
P0205 - Injector #5 Control Circuit
P0206 - Injector #6 Control Circuit

CODE 43 - Cylinder Misfire, or Ignition Primary Circuit

CODE $# MIL options: OBDII
P0300 - Multiple Cylinder Misfire
P0301 - Cylinder #1 Misfire
P0302 - Cylinder #2 Misfire
P0303 - Cylinder #3 Misfire
P0304 - Cylinder #4 Misfire
P0305 - Cylinder #5 Misfire
P0306 - Cylinder #6 Misfire
P0351 - Ignition Coil #1 Primary Circuit
P0352 - Ignition Coil #2 Primary Circuit
P0353 - Ignition Coil #3 Primary Circuit

douple ck all the ground wiresto engine,trans bell housing ,battery or frame/firewall look for any that may have separated from any pack of wires or broken off eyelets then thightnen all points,,.these grounds are very important to comp/injection controls and can cause a multi code problem like yours.

p0203 is for the #3 cylinder injectoer control circuit..possible causes are lack of voltage to the injector....a constant ground to the injector...an injector....or pcm