TPMS system

Pilotjcd · **Joined:** Tue Feb 12, 2019 6:20 pm **Posts:** 13

I need basic info on the tpms system. I just bought my 2006 limited crd and it has the low tire light as well as the tpm service warning in the overhead. I replaced one low tpms sensor and drove to reset with no luck. The jeep was in an accident and they replaced the front cap. I suspect that one of the two front sensors are missing or broken.
My questions are
1. Where exactly are the wheel well sensors located.
2. Where do the wires from the sensors run.
3. Where is the rear sensor located.
I am assuming that when they replaced the fenders they did not replace the sensors. I can pull from salvage yard but wanted to make sure I k SW what I needed.

Jay ne Ohio · **Joined:** Sun Dec 12, 2010 5:49 pm **Posts:** 216

The sensor is inside the tire and attached to the valve stem. I believe the spare tire even has a sensor. The battery is probably dead in at least one. I don't think you can replace the battery and therefore need to replace the entire sensor. The Jeep needs to be driven at over 20 mph for at least 10 minutes for the new sensor to be trained.

Here is a good overview: https://www.moderntiredealer.com/articl ... ms-sensors

papaindigo · **Posted:** Sat Mar 16, 2019 11:48 am

The linked article is accurate. As to your questions:
1. as noted each of the 5 tires from the factory came with an integrated valve stem/pressure sending unit - same as all TPMS systems as far as I know.
2. the sensors have no wires; they are radio transmitters. Battery powered by a not replaceable battery with a life span of 5-12 years and average of 7.
3. see 1 above.

You likely have 1 or more dead sensors but it is possible that the receiving module (e.g. whatever the individual wheel sensors send a signal too) was damage in the accident and not replaced. Unfortunately I have no clue where that module is or how to test it. The FSM that you can down load from http://colorado4wheel.com/manuals/Jeep/KJ/ might help some.

TKB4 · **Posted:** Tue Apr 02, 2019 1:21 am

here are the replacement sensors I used
https://www.amazon.com/gp/product/B001U ... 0DER&psc=1

GordnadoCRD · **Posted:** Tue Apr 02, 2019 2:16 am

IIRC on the 2006 model, the sensor reader modules are in the wheel-wells separated by the splash guards, and forward of the particular wheel/tire assembly.
And there are 3.
LF
RF
RR
The remaining one (LR) is identified by process of elimination.

TIRE PRESSURE MONITORING SYSTEM
DESCRIPTION
BASE TIRE PRESSURE MONITORING
This system will consist of tire pressure monitoring sensors attached to each wheel through the valve stem mounting hole, a central receiver module (WCM) and a yellow telltale. A sensor shall be installed in the spare wheel if the vehicle is equipped with a matching full size spare wheel and tire assembly.

PREMIUM TIRE PRESSURE MONITORING
The system will consist of tire pressure monitoring sensors attached to each wheel through the valve stem mounting hole, a wireless control module (WCM), Three Wheel Sensor transponders are mounted in the wheel wells (2 in the front and 1 in the rear wheel wells). a re-configurable dot matrix display module and an amber colored ISO standard Indicator Lamp. A sensor shall be installed in the spare wheel if the vehicle is equipped with a matching full size spare wheel and tire assembly.

WIRELESS CONTROL MODULE (WCM)
The receiver circuit for the TPM system is integrated into the WCM. The WCM also includes the Remote Keyless Entry (RKE) receiver and the Sentry Key Immobilizer (SKIM) receiver. All three receivers share a number or common components. The WCM decodes the RF signals transmitted by each of the vehicle’s tire pressure sensors. The decoded information is used to determine if "warning" or "fault" conditions exist within the TPM system. The WCM communicates with the module that controls the 9ISO Indicator Lamp and the text display (Premium system), via the vehicle bus system (CAN B).
Upon detection of a warning or fault condition, the WCM will send a request to illuminate the yellow telltale. Also, upon detection of a warning or fault condition, the display module will send a request to sound the chime. A chime will only be requested once per ignition cycle per warning or fault condition detected. The WCM will store all warning and fault conditions, placard pressure values, low-pressure threshold values and low pressure threshold hysterisis values in memory that can be accessed through diagnostic communication. If new sensors are introduced to the vehicle, the data stored for the sensor being replaced will be deleted. The WCM will store all wheel sensor ID’s and locations and faults in memory that can be accessed through diagnostic communication. All other data values transmitted from each active wheel sensor (not the spare tire) shall be stored in the WCM memory.

OPERATION
BASE TIRE PRESSURE MONITORING
The tire pressure monitoring system is designed to operate without loss of function for all types of standard tire constructions. (Function with different types of run flat tire constructions needs to be evaluated for each design). The wheel sensor shall monitor tire pressure, air temperature inside the tire, wheel acceleration and the sensor internal battery status for all four active road tires. The sensor will broadcast this information, along with a unique 32 bit ID, to a central receiver circuit located inside the WCM. The information received by the WCM will be decoded and stored in memory (RAM) in the WCM. If a warning or fault condition exists, the WCM will send a bus message request to illuminate the yellow telltale and to sound the chime. If the WCM detects a warning or fault condition at ignition key 9on9 it will wait ten seconds +/- 10 % before sending the first request to illuminate the yellow telltale. This will assure that the display module has concluded its bulb
check period. The display module will request a chime once per ignition cycle for each warning or fault condition detected. A warning or fault condition will remain enabled until the problem causing the condition is corrected and removed/reset.
The WCM shall continuously monitor for the receipt of tire pressure RF message transmissions from the wheel sensors during both the ignition key on and key off cycles. The wheel sensor ID’s and the location of each sensor (e.g. Tire 1, Tire 2 etc.) are stored in the WCM non-volatile memory during the initial Manufacturing Plant Process, or during a service procedure, as required. The recommended placard pressure, low-pressure threshold and “Hysteresis Pressure Values” for the tires installed on the vehicle, are stored in the WCM non-volatile memory during the initial Manufacturing Plant Process, or during a service procedure, as required. (Note: For vehicles with optional wheel/tire sizes and significantly different tire placard pressures, the placard pressure value and the low pressure threshold value shall be re-programmable by the dealer to accommodate the customer selected wheel/tire combinations recommended by DaimlerChrysler).

PREMIUM TIRE PRESSURE MONITORING
The tire pressure monitoring system is designed to operate without loss of function for all types of standard tire constructions. (Function with different types of run flat tire constructions needs to be evaluated for each design). The wheel sensor shall monitor tire pressure, air temperature inside the tire, wheel acceleration and the sensor internal battery status for all four active road tires and the spare tire, if so equipped. The sensor will broadcast this information, along with a unique 32 bit ID, to a central receiver circuit located inside the WCM. The information received by the WCM will be decoded and stored in (RAM) memory in the WCM. The WCM will send bus messages to the re-configurable display module to display the pressures of the four active road tires in vehicle position. The spare tire pressure is monitored but it is not displayed. If a "warning" or "fault" condition exists, the WCM will send a bus message request to display the text messages and, when required, illuminate the yellow telltale. "Warnings" and "faults" are described in more detail below. If the WCM detects a warning or fault condition at ignition key "on" it will wait ten seconds +/- 10% before sending the first request to illuminate the yellow telltale and to display the text messages. This will assure that the display module has concluded its bulb check period. The display module will request a chime once per ignition cycle for each "warning" or "fault" condition detected. A "warning" or "fault" condition will remain enabled until the problem causing the condition is corrected and removed/reset the WCM shall continuously monitor for the receipt of tire pressure RF message transmissions from the wheel sensors during both the ignition key "on" and key "off" cycles. The wheel sensor ID’s and the location of each sensor (e.g. Left Front, Right Front etc.) are stored in the WCM non-volatile memory during the initial Manufacturing Plant Process, or during a service procedure, as required. The recommended "placard pressure", "low-pressure threshold" and Hysteresis Pressure Values for the tires installed on the vehicle, are stored in the WCM non-volatile memory during the initial Manufacturing Plant Process, as described later in this document or during a service procedure as required. (Note: For vehicles with optional wheel/tire sizes and significantly different tire placard pressures, the placard pressure value and the low-pressure threshold value shall be re-programmable by the dealer to accommodate the customer selected wheel/tire combinations recommended by DaimlerChrysler).

DIAGNOSIS AND TESTING - TIRE PRESSURE MONITORING SYSTEM
All Tire Pressure Monitoring System Faults are specific to one location. If a "BATTERY LOW" or "SENSOR FAILURE" fault is detected, the location will be displayed (Premium Systems). The appropriate sensor/transmitter can then be replaced. If a single sensor/transmitter cannot be detected by the WCM, replace that sensor transmitter. If none of the sensors/transmitters can be detected, refer to symptoms in the WCM section. For additional system description and diagnosis, refer to Tire Pressure Monitoring in the Body Diagnostic manual.

Yada Yada. from the FSM Papaindigo linked.

TKB4 · **Posted:** Tue Apr 02, 2019 3:33 am

First I didn't read the whole FSM excerpt but I cannot understand how 3 sensors could get the 4th by a process of elimination since there is a fifth in the spare tire and I get a warning on the EVIC when the spare pressure is low also.

GordnadoCRD · **Posted:** Tue Apr 02, 2019 5:09 pm

TKB4 wrote:

First I didn't read the whole FSM excerpt but I cannot understand how 3 sensors could get the 4th by a process of elimination since there is a fifth in the spare tire and I get a warning on the EVIC when the spare pressure is low also.

The fifth is inactive, as it isn't on the road. Only if it were spinning, would it confuse the wireless module.

crasher · **Posted:** Mon Apr 15, 2019 3:29 pm

GordnadoCRD wrote:

TKB4 wrote:

First I didn't read the whole FSM excerpt but I cannot understand how 3 sensors could get the 4th by a process of elimination since there is a fifth in the spare tire and I get a warning on the EVIC when the spare pressure is low also.

The fifth is inactive, as it isn't on the road. Only if it were spinning, would it confuse the wireless module.

I have the fullsize tire/rim spare that I use for 5 tire rotations at 5K mile intervals.

My EVIC always tells me my 'spare is low', no matter the pressure, or which tire is mounted.

I've had it to ~2 Jeep dealers, who just scratched their heads, and several tire retailers with Snap-On scanners who verify that all tires are in pressure spec range and broadcasting proper pressure, did the air-up/air-down/air-up hokeypokey driving it around, and nobody ever had better than 'I dunno, beats the crap outta us' responses.

There was a thread about how doing the 'ignition key interlock' replacement resulted in jostled wires in the column that ended up triggering false TPMS/EVIC issues, but I haven't seen it lately, so I don't know if my search is weak, or if the thread was pulled.
I've wondered about how that thread panned out.

And it seems that the 2005 EVIC is different than the 2006, whether it comes from a diesel or not.
I've bought several with various claims, the ones that are supposed to say that a tire is low pressure, plus two that show vehicle outline with individual pressure at each tire location, and the only one that gives any usable tire pressure data is my original that tells me specifically that my spare tire is low.

I used to enjoy wrenching, and building 396's to replace 400's in two old '72 era Formula Firebirds.
I had a new '77 Powerwagon that spent more time frying electronic modules and voltage regulators/batteries/etc than it spent being reliable.
I'm getting to be too old to enjoy the challenge the way I used to.

:5SHOTS:

Edited for clarity.

ebbnflow · **Posted:** Tue Apr 16, 2019 1:32 pm

You can disable the tpms system with a drbiii or a micropod.

taroo · **Joined:** Sun Apr 27, 2008 2:14 pm **Posts:** 271

TKB4 wrote:

here are the replacement sensors I used
https://www.amazon.com/gp/product/B001U ... 0DER&psc=1

Okay...so if I buy these, will a shop replace them for me? Won't they require that I buy the sensors from them?

taroo · **Joined:** Sun Apr 27, 2008 2:14 pm **Posts:** 271

taroo wrote:

TKB4 wrote:

here are the replacement sensors I used
https://www.amazon.com/gp/product/B001U ... 0DER&psc=1

Okay...so if I buy these, will a shop replace them for me? Won't they require that I buy the sensors from them?

If I buy these and have a tire shop install them, is there anything needed to "program" the system to accept them or do you just start rolling and all works correctly?

TPMS system

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