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Scott
Scott, Technician
Category: Jeep
Satisfied Customers: 1190
Experience:  Dodge,Chrysler,Jeep Master Tech since 92.ASE Master since 1990.Currently Dealer employed.
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wiring diagrams for under hood and dash 1998 jeep wrangler

Resolved Question:

wiring diagrams for under hood and dash 1998 jeep wrangler
Submitted: 3 years ago.
Category: Jeep
Expert:  Scott replied 3 years ago.

Scott :

Hello, The wiring diagrams are not "continous" They are formated by specific circuits or componets - like this .[IMAGE][SRC][/SRC][ALT]tj808606[/ALT][WIDTH]100[/WIDTH][HEIGHT]100[/HEIGHT][STYLE][/STYLE][/IMAGE] There are at least 15 pages like this just for the cluster. What circuits do you need - or what are you trying to do?

Scott :

Lets try again.

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Expert:  Scott replied 3 years ago.
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Expert:  Scott replied 3 years ago.
We can send all the pages need - Scott.
Customer: replied 3 years ago.
i am trying to track down a short car won't start no fire to plugs no gauges have no bus on mileage reading i have changed the cps but did't fix it
Expert:  Scott replied 3 years ago.

Ok- Thanks. I assume you have checked all the fuses ? We often see this problem when the engine computer fails or battery acid has damaged the wiring of the computer.

We test for a failing computer by moving the three connectors slightly to see if the engine will restart. We also look for acid damage to the wiring.Let me know if you want more info- I can send the diagnostics from the manual- It basically has you test the wires that communicate to the rest of the modules, test for power and ground at the computer connector- then replace the computer- Of course there are many other steps- but you need to have a scan tool that can read the engine and other modules- like the cluster and air bag , brakes, ect..Let me know what you find when you move the engine computer connectors. Thanks Scott.

Customer: replied 3 years ago.
i have uplug all the sensos one at a time to check them i have found that unhookig the neg. battery post and with atest meter between the cable and the post i get 12 volts with everything off when i unplug the 50 amp fuse it goes away i have also checked the comp. plugs they seam ok thats why i need to check the wiring i think there is a short somewhere
Expert:  Scott replied 3 years ago.

Ok, I will send the info that I think will help the most.

Using a voltmeter as described will always show 12 volts unless the fuse is pulled that supplies memory power to the radio, air bag,computer, cluster. The 50 amp fuse must also supply the power for the memories.

The problem with the engine computer not communicating with the cluster can be caused by many different problem . The most often computer failure is caused by loose power connection inside the computer on the circuit board. Moving the connectors will sometimes cause the loose connection inside to reconnect - this would make the relays to click and the cluster to start working again.And the engine to start. The relays would only click if the key was on. Some computer failures will not respond to tapping the computer or moving the connectors. A Shorted sensor can cause the engine to not start.

On the rear of the engine on the drivers side valve cover there is a stud that can rub into the wiring harness, Inspect that area.

We test for shorted sensors by eliminating them one at a time. We start at the crank sensor, cam sensor, tps, map sensor ,o2 sensors ect.. We disconnect one sensor- cycle the key on check to see if the no buss returns- or we will connect the volt meter to the tps sensor and watch to see if the 5 volt supply returns after a sensor is disconnected. You will have to disconnect all the sensors one at a time.

I will gather more info, I will be back. Thanks Scott.

 

 

Scott, Technician
Category: Jeep
Satisfied Customers: 1190
Experience: Dodge,Chrysler,Jeep Master Tech since 92.ASE Master since 1990.Currently Dealer employed.
Scott and 6 other Jeep Specialists are ready to help you
Customer: replied 3 years ago.
i have unhooked all the sensors one at time as you said and i still have no guages and the no bus on the mileage and no fire to the plugs could it be a bad comp. and all the fuses are good what happened was my son was on his way home and hit a bump and all the iside lights went off and all the guages but it was still running till he sut it off the net time he went to start it up it would not start i have plug a tester in to the under dash plug and we did not get any readings from the comp.
Expert:  Scott replied 3 years ago.

This is 1/5 of the info - more to follow. I read your post before I posted- I think you have a bad computer. Try tapping on it while some one cranks it over. Let me know if you need the other 4/5 of the dianostic for this

 

Symptom:

* ENGINE DOES NOT START & DRB DISPLAYS NO RESPONSE

POSSIBLE CAUSES

NO RESPONSE DISPLAYED

ASD RELAY OUTPUT CIRCUIT SHORTED TO GROUND

DRB ADAPTER CABLE

FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN

IGNITION COIL

PCM 5-VOLT PRIMARY SUPPLY CIRCUIT SHORTED TO GROUND

PCM 5-VOLT SECONDARY SUPPLY CIRCUIT SHORTED TO GROUND

TPS GROUND CIRCUIT SHORTED TO VOLTAGE

CAMSHAFT POSITION SENSOR

CRANKSHAFT POSITION SENSOR

FUEL INJECTOR(S)

GENERATOR SHORTED TO GROUND

OIL PRESSURE SENDING UNIT

SCI RECEIVE CIRCUIT OPEN

SCI RECEIVE CIRCUIT SHORTED TO GROUND

SCI TRANSMIT CIRCUIT OPEN

SCI TRANSMIT CIRCUIT SHORTED TO GROUND

DRB

MANIFOLD ABSOLUTE PRESSURE SENSOR

O2 SENSOR(S)

PCM DEFECTIVE (NO RESPONSE)

PCM GROUND CIRCUIT(S) OPEN

POWERTRAIN CONTROL MODULE (NS-6D)

VEHICLE SPEED SENSOR

FUSED B(+) CIRCUIT OPEN BETWEEN FUSE/BATTERY

FUSED B(+) CIRCUIT SHORTED TO GROUND

FUSED B(+) CIRCUIT OPEN BETWEEN FUSE/PCM

LEAK DETECTION PUMP

STARTING

TEST ACTION APPLICABILITY

1 Key off.

Disconnect the Powertrain Control Module Black Connector.

Note: Check connectors - Clean/repair as necessary.

Using an Ohmmeter, measure both Ground Circuits at PCM Connector.

Is the resistance below 5.0 ohms at both Terminals?

All

Yes - Go To 2

No -Repair the open ground(s) at the Powertrain Control Module.

2 -Key off.

Disconnect the Powertrain Control Module Black Connector.

Note: Check connectors - Clean/repair as necessary.

Turn ignition on.

Using a Voltmeter, measure the Fused Ignition Switch Output Circuit.

Is the voltage above 10.0 volts?

All

Yes -Go To 3

No - Repair the open Fused Ignition Switch Output Circuit between

PCM & Ignition Switch.

3 -Key off.

Disconnect the Powertrain Control Module Black Connector.

Note: Check connectors - Clean/repair as necessary.

With a Voltmeter, measure the Fused B(+) Circuit in the PCM Connector.

Is the voltage above 10.0 volts?

All

Yes - Go To 4

No - Go To 13

4- Ignition Off

Disconnect the Throttle Position Sensor.

Note: Check connectors - Clean/repair as necessary.

Ignition key on.

Connect a Voltmeter to the Throttle Position Sensor 5-Volt Supply Circuit.

Is the voltage below 4.0 volts?

All

Yes - Go To 5

No -Replace the Powertrain Control Module.

.

5 -Ignition Off

Disconnect the Camshaft Sensor.

Note: Check connectors - Clean/repair as necessary.

Ignition key on.

Connect a Voltmeter to the Camshaft Position Sensor 5-Volt Supply Circuit.

Read Voltmeter.

Is the voltage below 4.0 volts?

All

Yes -Go To 6

No - Replace the Camshaft Sensor.

279

STARTING

* ENGINE DOES NOT START & DRB DISPLAYS NO RESPONSE -

Continued

TEST ACTION APPLICABILITY

6 -Ignition Off

Disconnect the Crankshaft Sensor.

Note: Check connectors - Clean/repair as necessary.

Ignition key on.

Connect a Voltmeter to the Crankshaft Position Sensor 5-volt Supply Circuit.

Read Voltmeter.

Is the voltage below 4.0 volts?

All

Yes Go To 7

No - Replace the Crankshaft Sensor.

Perform Powertrain Verification Test VER-1.

7 -Ignition Off

Disconnect the MAP Sensor.

Note: Check connectors - Clean/repair as necessary.

Ignition key on.

Connect a Voltmeter to the Manifold Absolute Pressure Sensor 5-Volt Supply Circuit.

Read Voltmeter.

Is the voltage below 4.0 volts?

All

Yes - Go To 8

No - Replace the MAP Sensor.

8 - Ignition Off

Disconnect the Vehicle Speed Sensor.

Note: Check connectors - Clean/repair as necessary.

Ignition key on.

Connect a Voltmeter to the Vehicle Speed Sensor 5-Volt Supply Circuit.

Read the Voltmeter.

Is the voltage below 4.0 volts?

All

Yes - Go To 9

No - Replace the Vehicle Speed Sensor.

.

9 - - Ignition Off

Disconnect the Oil Pressure Sending unit.

Note: Check connectors - Clean/repair as necessary.

Read the voltmeter.

Is the voltage below 4.0 volts?

All

Yes - Go To 10

No - Replace the Oil Pressure Sending unit.

10 Ignition Off

Disconnect the Throttle Position Sensor.

Note: Check connectors - Clean/repair as necessary.

Ignition On, Engine Not Running.

Measure the voltage of the Sensor Ground Circuit at TPS Connector.

Is the voltage above 1.0 volt?

All

Yes -- Repair the Sensor Ground Circuit shorted to voltage.

.

No - Go To 11

280

STARTING

* ENGINE DOES NOT START & DRB DISPLAYS NO RESPONSE -

Continued

TEST ACTION APPLICABILITY

11--- Ignition Off

Disconnect the Throttle Position Sensor.

Disconnect the Camshaft Sensor.

Disconnect the Crankshaft Sensor.

Disconnect the MAP Sensor.

Disconnect the Vehicle Speed Sensor.

Disconnect the Oil Pressure Sending Unit.

Note: Check connectors - Clean/repair as necessary.

Disconnect the Powertrain Control Module.

With an Ohmmeter, measure the resistance of the 5-Volt Primary Supply Circuit to

ground at the Powertrain Control Module Connector.

Is the resistance below 5.0 ohms?

All

Yes - Repair the shorted 5-Volt Primary Supply shorted to ground.

Perform Powertrain Verification Test VER-1.

No - Go To 12

12 Ignition Off

Disconnect the Throttle Position Sensor.

Disconnect the Camshaft Sensor.

Disconnect the Crankshaft Sensor.

Disconnect the MAP Sensor.

Disconnect the Vehicle Speed Sensor.

Disconnect the Oil Pressure Sending Unit.

Disconnect the Powertrain Control Module.

Note: Check connectors - Clean/repair as necessary.

With an Ohmmeter, measure the resistance of the 5-Volt Secondary Supply Circuit to

ground at the Powertrain Control Module Connector.

Is the resistance below 5.0 ohms?

All

Yes - Repair the shorted 5-Volt Secondary Supply shorted to ground.

Perform Powertrain Verification Test VER-1.

No - Go To 23



Edited by Scott on 10/14/2010 at 4:10 AM EST
Customer: replied 3 years ago.
<p>i just checked the asd relay and according to the #87 connection it is grounded is supposed to be that why i was wantin the wiring diagrams my hanes manual does not show very much</p><p>when this first happened the 15 amp fuse under the hood #1 ithink idon't have an owners manual to be sure it blowed out the guages , iterior lights, radio all went out also the under hood light is in this circuit i have disconnected this the wire that this is attached to goes to both sides of the car the one that goes to the passenger side has a rereverse ground than the one going to the drivers side so i thik it is shorted some where according to my hanes manuel it is the m1-18pk wire from what i can tell it is supposed be 12volt + i don't what else it goes to no wire digrams</p>

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