What is the purpose of circuit m34 in the harness?

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radio adapter harness by , Scosche

that name in japan means "little bit"
been there 10+ times, even into drydock. there,
that is there job to cure this and not need to wreck ANY factory harness with cutters.

Shorted sensor circuits are, fortunately, not lethal. You have 3 1/2 options.
1) disconnect harness and pull out to where you can work on chafed area, separate wires and re-insulate with electrical tape
2) replace harness with new or good used
3) repair chafed area with new wire segments.
3 1/2) have someone do it for you
Whichever route you go, protect the wires with some of the inexpensive split corrugated conduit sold for the purpose.

http://www.freeautomechanic.com/wiringdiagrams.html
Check out this site... maybe they have what you need.

Shift sensors are indicators for a computer controlled circuit. Most times, they are contained or housed within a solenoid pack. As they are an electronic monitor, the area they are housed in will usually have a multi-pin wiring harness leading to it. The harness connector is normally protected with a rubber grommet around it. I have seen these grommets "folded over/pinched" during assembly line installation. The purpose of the grommet is to form a water proof barrier within the harness connection. As this is a 4x4, it most likely sees somewhat rougher conditions and exposure. Any ammount of water spraythat reaches a weakened grommet is likely to penetrate through to the alloy electrical terminals. These "pins" rarely rust, but they DO corrode. The fine, powdery, blue corrosion inside the connections can act like an insulator and corrupt the signal. If disconnecting the harness pigtail is possible, physically look into the harness ends and at the pins. If there IS corrosion, try tapping the harness end against the transmission or transfercase to dislodge any loose particles. Usually, just a quick burst of air is enough to clear out the connection on the vehicle. Sometimes, that's all it takes. If there IS corrosion evident, FILL the cavity containing the pins with a dielectric gel/grease, before reinstalling the pigtail. DO NOT use silicone!

Absolutely YES! The bearing and hub assembly contains the wheel speed sensor which is used by the Antilock Brake System (ABS) and the Traction Control (TC) system to see when a wheel is trying to lock up and cause skidding. The ABS will release the hydraulic pressure to the brake on that wheel and the traction control will reduce engine speed to prevent the wheel from locking up or causing you to spin out.
Many GM vehicles also commonly have problems with the wiring harnesses to the wheel speed sensors that can cause this same problem. The computer does not know WHY it cannot read the speed sensor signal. It only knows that it is not getting the signal and this is why the light is turned on. Before paying the BIG BUCKS for a wheel bearing and hub assembly, it would be wise to make absolutely certain that the problem is not being caused by a fault in the wiring harness. I have seen many mechanics automatically replace the wheel bearing only to find out that the problem still exists because they did not take the time to DIAGNOSE the problem. The fault code description says "Wheel Speed Sensor CIRCUIT fault." They see "speed sensor and automatically replace the sensor without actually checking the circuit. Not a problem unless you are the customer having to PAY for this type of guess-work!!!

There are wiring harness repair kits available for MOST GM vehicles just for this purpose.

I have included pictures of the bearing and hub assembly and the wiring harness kit to help you understand what we are talking about here.

Note the electrical connector sticking out of the hub assembly. This is the wires to the speed sensor. In the other picture, the connector at the end of the wiring harness is what plugs into the connector in the hub assembly. The other end of it gets spliced into the main vehicle harness in the engine compartment, after cutting the original harness out.

WHEEL BEARING AND HUB ASSEMBLY



WIRING HARNESS REPAIR KIT

DTC P0243 - Turbo/Super Charger Wastegate Solenoid A
Description: Open or shorted condition detected in the turbocharger wastegate solenoid control circuit.


Here is the flow chart for that code (some images could need to clicking for zoom)...

P0243-WASTEGATE PRESSURE CONTROL PWM



For a complete wiring diagram Refer to Section 8W.

When Monitored: When the ignition is on.
Set Condition: The ECM detects an open or short circuit in the Wastegate solenoid circuit.

Possible Causes
DAMAGED WIRING HARNESS OR CONNECTORS
WASTEGATE SOLENOID
(F504) FUSED IGNITION SWITCH OUTPUT OPEN
(K139) WASTEGATE SOLENOID DRIVER CIRCUIT OPEN
(K139) WASTEGATE SOLENOID CIRCUIT SHORTED TO GROUND
(K139) WASTEGATE SOLENOID DRIVER SHORTED TO VOLTAGE
(K139) WASTEGATE SOLENOID DRIVER CIRCUIT SHORTED TO ANOTHER CIRCUIT
ECM
INTERMITTENT CONDITION

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

Diagnostic Test
1. DAMAGED WIRING HARNESS OR CONNECTORS



Turn Ignition off.
Disconnect the ECM harness connectors.
Disconnect the Wastegate Solenoid harness connector.

NOTE: Check connectors - Clean/repair as necessary.


Are any wires or pins damaged?

Yes
Repair or replace any damaged wire or connectors.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).

No
Go To 2


2. WASTEGATE SOLENOID



Reconnect the ECM harness connector.
Reconnect the disconnected Wastegate Solenoid harness connector.
Turn the Ignition on, engine not running.
Disconnect the Wastegate Solenoid harness connector.
Connect an incandescent test light across the supply and driver pins at the Wastegate Solenoid harness connector.

NOTE: The ECM will perform a self check of the circuit after approximately 30 seconds, which should light the incandescent test light.


Does the light illuminate brightly after 30 seconds of being connected?

Yes
Replace the Wastegate Solenoid.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).

No
Go To 3


3. (F504) FUSED IGNITION SWITCH OUTPUT OPEN



Connect an test light between the Wastegate Solenoid connector Fused ignition switch output circuit and battery negative.
Compare the test light brightness to that of a direct connection to the battery.

Does the light illuminate brightly?
Yes
Go To 4

No
Repair the open (F504) Fused Ignition switch output circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).



4. (K139) WASTEGATE SOLENOID DRIVER CIRCUIT OPEN



Disconnect the ECM harness connectors.
Measure the resistance of the Wastegate Solenoid driver circuit between the Wastegate Solenoid harness connector and the ECM harness connector.

Is the resistance less than 10 Ohms?
Yes
Go To 5

No
Repair the open (K139) Wastegate Solenoid control circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).


5. (K139) WASTEGATE SOLENOID CIRCUIT SHORTED TO GROUND



Measure the resistance of the (K139) Wastegate Solenoid driver circuit between the Wastegate Solenoid harness connector and battery negative.

Is the resistance less than 10 Ohms?
Yes
Repair the (K139) Wastegate solenoid circuit shorted to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).

No
Go To 6


6. (K139) WASTEGATE SOLENOID DRIVER SHORTED TO VOLTAGE



Measure the voltage between the (K139) Wastegate Solenoid driver circuit at the Wastegate Solenoid connector and battery negative.

Is the voltage less than 1 volt?
Yes
Go To 7

No
Repair the (K139) Wastegate solenoid driver shorted to voltage.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).


7. (K139) WASTEGATE SOLENOID DRIVER CIRCUIT SHORTED TO ANOTHER CIRCUIT



Measure the resistance between the (K139) Wastegate Solenoid driver circuit in the ECM harness connector and all other circuits in the ECM harness connectors.

Is the resistance less than 10 Ohms?
Yes
Repair the (K139) Wastegate solenoid circuit shorted to another circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)


No
Go To8


8. WASTEGATE SOLENOID


Reconnect the ECM harness connector.
Reconnect the disconnected Wastegate Solenoid harness connector.
Turn the Ignition on, engine not running.
Disconnect the Wastegate Solenoid harness connector.
Connect an incandescent test light across the supply and driver pins at the Wastegate Solenoid harness connector.

NOTE: The ECM will perform a self check of the circuit after approximately 30 seconds, which should light the incandescent test light.


Does the light illuminate brightly after 30 seconds of being connected?
Yes
Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure).

No
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).

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Possible Cause
The following items may be area of concern:
?¬Other transmission-related DTCs are set.
?¬Solenoid pack connector 5-volt supply circuit open.
?¬Sensor signal circuit has short to ground, short to voltage or open.
?¬Governor pressure sensor defective.
?¬Transmission fluid burnt or oil pan contains excessive debris.
?¬Governor pressure out of range.
?¬Transmission leaking internally.
?¬Defective PCM.
?¬Defective valve body.

Diagnostic Procedure
1.Using scan tool, read DTCs. If good trip counter for DTC P1756 is not displayed or displayed count is not zero, go to step 25. If good trip counter is displayed and displayed count is zero, go to next step.
2.Repair any other transmission-related DTCs before proceeding. If no other transmission-related DTCs exist, go to next step.
3.Check transmission fluid for proper level and for any debris. Fill or repair transmission as necessary. If fluid level and condition are okay, go to next step.
4.Start engine. Allow engine to reach normal operating temperature. Set parking brake, depress brake pedal and place gearshift lever in "D" position. Using scan tool, observe governor pressure sensor pressure. If pressure is greater than 3 psi (.2 kg/cm 2 ), go to next step. If pressure is 3 psi (.2 kg/cm 2 ) or less, go to step 20.
5.Turn ignition off. Install a pressure gauge at transmission governor pressure test port. Start engine. With gearshift lever in "D" position, observe gauge pressure. If pressure is 5 psi (.3 kg/cm 2 ) or more, go to step 23. If pressure is less than 5 psi (.3 kg/cm 2 ), go to next step.
6.Turn ignition off. Disconnect transmission solenoid assembly connector. Turn ignition on. Measure voltage between ground and 5-volt supply circuit at transmission solenoid harness connector terminal No. 2. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 19.
7.Turn ignition off. Disconnect PCM harness connector C2 (White). Measure resistance of governor pressure sensor signal circuit between transmission solenoid harness connector terminal No. 4 and PCM harness connector C2 (White) terminal No. 29. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair governor pressure sensor signal circuit for open.
8.Disconnect PCM harness connector C1 (Black). Measure resistance of sensor ground circuit between transmission solenoid harness connector terminal No. 3 and PCM harness connector C1 (Black) terminal No. 4. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair sensor ground circuit for open.
9.Measure resistance of governor pressure sensor signal circuit between ground and transmission solenoid harness connector terminal No. 4. If resistance is less than 5 ohms, repair signal circuit for short to ground. If resistance is 5 ohms or more, go to next step.
10.Measure resistance between sensor signal circuit and sensor ground circuit at transmission solenoid harness connector terminals No. 3 and 4. If resistance is less than 5 ohms, repair governor pressure sensor circuit for short to sensor ground circuit. If resistance is 5 ohms or more, go to next step.
11.Turn ignition on. Measure voltage of governor pressure sensor signal circuit between ground and transmission solenoid assembly connector terminal No. 4. If voltage is one volt or less, go to next step. If voltage is more than one volt, repair sensor signal circuit for short to voltage.
12.Turn ignition off. Ensure transmission solenoid harness connector is disconnected. Remove transmission oil pan. Disconnect governor pressure/temperature sensor harness connector. Inspect connector and terminals for damage. Repair as necessary. Measure resistance of governor pressure sensor 5-volt supply circuit between governor pressure/temperature sensor harness connector terminal "A" and transmission solenoid harness connector terminal No. 2. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, replace transmission solenoid assembly (internal transmission harness).
13.Measure resistance of sensor ground circuit between governor pressure/temperature sensor harness connector terminal "D" and transmission solenoid harness connector terminal No. 3. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, replace transmission solenoid assembly (internal transmission harness).
14.Measure resistance of governor pressure sensor signal circuit between governor pressure/temperature sensor harness connector terminal "B" and transmission solenoid harness connector terminal No. 4. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, replace transmission solenoid assembly (internal transmission harness).
15.Measure resistance of governor pressure sensor signal circuit between ground and governor pressure/temperature sensor harness connector terminal "B". If resistance is less than 5 ohms, replace transmission solenoid assembly (internal transmission harness). If resistance is 5 ohms or more, go to next step.
16.Measure resistance between governor pressure sensor signal circuit and sensor ground circuit at governor pressure/temperature sensor harness connector terminals "B" and "D". If resistance is less than 5 ohms, replace transmission solenoid assembly (internal transmission harness). If resistance is 5 ohms or more, go to next step.
17.Reconnect transmission solenoid assembly harness connector. Turn ignition on. Measure voltage of governor pressure sensor signal circuit between ground and governor pressure/temperature sensor harness connector terminal "B". If voltage is more than one volt, replace transmission solenoid assembly (internal transmission harness). If voltage is one volt or less, go to next step.
18.Turn ignition off. Using DVOM, backprobe governor pressure sensor signal circuit at PCM harness connector C2 (White) terminal No. 29. Start and idle engine. Place gearshift lever in "N" position. Using scan tool, observe governor pressure sensor voltage. Compare scan tool value with DVOM voltage. If voltages match, replace governor pressure/temperature sensor. If voltages do not match, replace PCM.
19.Turn ignition off. Ensure transmission solenoid harness connector is disconnected. Disconnect PCM harness connector C2 (White). Measure resistance of 5-volt supply circuit between transmission solenoid harness connector terminal No. 2 and PCM harness connector C2 (White) terminal No. 31. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair 5-volt supply circuit for open.

NOTE: Removing transmission control relay in the following step may set other DTCs. Disregard these DTCs.

Open the rear hatch and look for the wiring harness that goes into the door. Inspect the harness for cut or damaged wires. Also look for failed fused links. These are wires that are design to fail when the circuit is over loaded or shorted. They serve the same purpose as fuses but usually more than one circuit is wired thru them. If you dont find anything wrong then you will need to aquire a wiring diagram to further trouble the circuits.