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Instructor JP
Instructor JP, Technical Instructor master ASE
Category: Jeep
Satisfied Customers: 315
Experience:  Jeep Manufacture Instructor 14 years
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Jeep grand cherokee: speedometer..speed sensor abs light light

Resolved Question:

02 jeep grand cherokee p0500 no speedometer have replaced speed sensor abs light light on no data from abs computer
Submitted: 5 years ago.
Category: Jeep
Expert:  Instructor JP replied 5 years ago.

HelloCustomer

 

DO you have a manual transmission?

Can I have your engine size please?

Abs controler may only comunicate with the dealer scan tool.

 

jp

Customer: replied 5 years ago.

I have an automatic trans

engine size 4.0

 

Expert:  Instructor JP replied 5 years ago.

Ok thank you,

 

The vehicle speed comes from the ABS controller by averaging the two axles speeds and sends it to the communication network. The engine controller picks up the signal and provides you with the speed. You have to be able to talk or interrogate the ABS controller to see if there is a problem within the brake system. The next step is to look in the engine controller for the speed signal from the ABS. If you are using a scan tool that can talk to the abs and abs is unresponsive than you may need a work with the ABS.

 

here are the diagnostic steps

 

P0500-NO VEHICLE SPEED SENSOR SIGNAL

When Monitored and Set Condition:

P0500-NO VEHICLE SPEED SENSOR SIGNAL

When Monitored: Engine Temperature greater than 104 deg F. , MAP vacuum approximately

159 to 169 inches of mercury and Engine RPM between 1400 and 3000 rpm.

Set Condition: No Vehicle Speed Signal for more than 15 seconds on two consecutive

trips.

POSSIBLE CAUSES

INTERMITTENT CONDITION

VEHICLE SPEED SIGNAL CIRCUIT OPEN

VEHICLE SPEED SIGNAL CIRCUIT SHORTED TO GROUND

VEHICLE SPEED SIGNAL CIRCUIT SHORTED TO VOLTAGE

PCM

TEST ACTION APPLICABILITY

1 Ignition on, engine not running.

With the DRBIIIt, read DTCs.

NOTE: Any VSS DTCs in the CAB Module or Body Controller must be

properly diagnosed before continuing.

Is the Good Trip Counter displayed and equal to zero?

All

Yes ! Go To 2

No ! Go To 6

2 Turn the ignition off.

Disconnect the Powertrain Control Module harness connectors.

Disconnect the ABS Control Module harness connector.

Measure the resistance of the Vehicle Speed Signal circuit between the PCM harness

connector and the ABS Control Module harness connector.

Is the resistance above 5.0 ohms?

All

Yes ! Repair the open Vehicle Speed Signal circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No ! Go To 3

3 Turn the ignition off.

Disconnect the Powertrain Control Module harness connectors.

Disconnect the ABS Control Module harness connector.

Measure the resistance between ground and the Vehicle Speed Signal circuit at the

PCM harness connector.

Is the resistance below 100 ohms?

All

Yes ! Repair the short to ground in the Vehicle Speed Signal circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

 

 

 

TION APPLICABILITY

 

4 Turn the ignition off.

Disconnect the PCM harness connector.

Ignition on, engine not running.

Measure the voltage on the Vehicle Speed Signal circuit at the PCM harness

connector.

Is the voltage above 4.8 volts?

All

Yes ! Repair the short to voltage in the Vehicle Speed Signal circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No ! Go To 5

5 If there are no possible causes remaining, view repair. All

Repair

Replace and program the PCM in accordance with the Service

Information.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

6 NOTE: The conditions that set the DTC are not present at this time. The

following list may help in identifying the intermittent condition.

WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A

DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE

PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.

 

With the engine running at normal operating temperature, monitor the DRBIIIt

parameters related to the DTC while wiggling the wiring harness. Look for parameter

values to change and/or a DTC to set.

Review the DRBIIIt Freeze Frame information. If possible, try to duplicate the

conditions under which the DTC was set.

Refer to any Technical Service Bulletins (TSB) that may apply.

Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or

partially broken wires.

Visually inspect the related wiring harness connectors. Look for broken, bent, pushed

out, or corroded terminals.

Were any of the above conditions present?

All

Yes ! Repair as necessary or refer to the proper ABS Diagnostic Manual

and perform the appropriate symptom diagnostics.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

Expert:  Instructor JP replied 5 years ago.

As you can see if you can read thru the whole diagnosis process, You may have a wiring problem or a controller issue. Scan tool is a must here so you do not spend any more on parts without fixing the issue.

 

Let me know if you need more..

 

jp

Expert:  Instructor JP replied 5 years ago.

Thank you for using Justasnwers. Please press the accept button so the expert can receive a portion of the fee for his / her advice and guidance.

Customer: replied 5 years ago.
My Mitchell info shows the vehicle sp sens goes thru the pcm first. Does your info show that it goes to the abs controller first? I do have brake light and ABS light on - could be possible abs cont module. I have no speed sens reading thru scan tool. The speed sensor resistor does check out from the pcm to the speed sensor and produces an a/c millivolt. Have no scope. Have tried an used unflashed pcm - security light was active but no speedometer operation.
Expert:  Instructor JP replied 5 years ago.

 

The speed sensor on the transmission is an input to the PCM for transmission control.

Here is the service manual description of speedometer function.

 

The PCM continually monitors the vehicle speed information received from the Controller Anti-lock Brake (CAB) to determine the vehicle road speed, then sends the proper vehicle speed messages to the instrument cluster. For further diagnosis of the speedometer or the instrument cluster circuitry that controls the gauge, For proper diagnosis of the CAB, the PCM, the PCI data bus, or the electronic message inputs to the instrument cluster that control the speedometer, a DRBIII® scan tool is required. Refer to the appropriate diagnostic information.

 

Customer: replied 5 years ago.
I do not have a DRBIII scan tool so what is the appropriate diagnostic info? Best guess for problem?
Expert:  Instructor JP replied 5 years ago.
Customer

 

You must be able to interrogate the ABS controller to know what or which controller has the issue. Your ABS light is on and you can not talk to it with a your scan tool, it is questionable to me about which direction to go.

1 Is your ABS controller bad?

2 Do you have a bad sensor for the ABS?

3 You may have a bad cracked tone wheel. the sensor checks out fine but the reading is off shutting down the ABS.

 

You need the dealer scan tool to continue unless you do the 50% rule. replace everything up to 50% and then use the dealer scan tool and spend 50% more to fix the Jeep. Not trying to be mean just from experience..

 

jp

Instructor JP, Technical Instructor master ASE
Category: Jeep
Satisfied Customers: 315
Experience: Jeep Manufacture Instructor 14 years
Instructor JP and 5 other Jeep Specialists are ready to help you

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