# Service bulletin 18\-014\-20 REV. A

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Service bulletin
- NHTSA id: 10174232
- Published by NHTSA: 2020\-04\-27
- Manufacturer's number: 18\-014\-20 REV. A
- Manufacturer's date: 2020\-03\-18
- NHTSA component: ELECTRICAL SYSTEM; POWER TRAIN

## NHTSA's summary

Flash: Powertrain Control Module \(PCM\) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp \(MIL\) illumination. Upon further investigation the technician may find that one or more of the following DTCs have been set:P0456 \- EVAP System Small Leak.If DTC P0456 is present use wiTECH Small Leak Verification Test \(SLVT\) to determine if a leak is present in the system. P0171 \- Fuel System 1/1 Lean\(LATAM Only\). P0172 \- Fuel System 1/1 Rich\(LATAM Only\). P0128 \- Thermostat Rationality\(APAC\&EMEA with Sales Codes NA1 with NBQ or NB6 Only\). P050B \- Cold Start Ignition Timing Performance\(APAC\&EMEA with Sales Codes NA1 with NBQ or NB6 Only\). Customers may experience:Excessive fan noise when the A/C is on MAX output. Rough idle at engine start up in colder ambient emperatures. Software enhancements include:Electric Vacuum Pump \(EVP\) update. Fan noise reduction. Low Speed Pre Ignition \(LSPI\) update.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2020/MC-10174232-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2020/MC-10174232-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Electrical system, Transmission and driveline

## Trouble codes named

P0128, P0171, P0172, P0456, P050B

## Vehicles listed

- 2018 JEEP WRANGLER

## Recalls for the same vehicles and component

- [24V652000](/recalls/nhtsa/24V652000.md), 2024-09-05: ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL
- [2023089](/recalls/tc/2023089.md), 2023-02-23: Powertrain
- [23V116000](/recalls/nhtsa/23V116000.md), 2023-02-23: POWER TRAIN:CLUTCH ASSEMBLY
- [2021035](/recalls/tc/2021035.md), 2021-01-28: Powertrain
- [21V028000](/recalls/nhtsa/21V028000.md), 2021-01-28: POWER TRAIN:CLUTCH ASSEMBLY
- [2020083](/recalls/tc/2020083.md), 2020-03-03: Powertrain
- [20V124000](/recalls/nhtsa/20V124000.md), 2020-03-03: POWER TRAIN:CLUTCH ASSEMBLY
- [2018422](/recalls/tc/2018422.md), 2018-08-09: Powertrain
- [18V524000](/recalls/nhtsa/18V524000.md), 2018-08-09: ELECTRICAL SYSTEM:WIRING:FRONT UNDERHOOD
- [18V332000](/recalls/nhtsa/18V332000.md), 2018-05-17: ELECTRICAL SYSTEM:SOFTWARE; VEHICLE SPEED CONTROL:CRUISE CONTROL; ELECTRICAL SYSTEM:WIRING

## Other bulletins for the same vehicles and component

- [08\-363\-26](/bulletins/11038523.md), 2026-10-16, Service bulletin: ELECTRICAL SYSTEM. Flash: Drivetrain Control Module \(DTCM\) Updates Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must SYMPTOM: exhibit/set the following Diagnostic Trouble Code \(DTC\): ● C147B\-92 \- Front Axle Disconnect Sensor Performance or Incorrect Operation Customers may comment on one or more of the following: ● 4WD system warning lights, service messages, or flashing indicators are displayed in the Instrument Panel Cluster \(IPC\). ● The vehicle does not engage 4WD properly. This bulletin involves reprogramming the DTCM with the latest available software.
- [08\-363\-26](/bulletins/11038486.md), 2026-10-16, Service bulletin: ELECTRICAL SYSTEM. Flash: Drivetrain Control Module \(DTCM\) Updates Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must SYMPTOM: exhibit/set the following Diagnostic Trouble Code \(DTC\): ● C147B\-92 \- Front Axle Disconnect Sensor Performance or Incorrect Operation Customers may comment on one or more of the following: ● 4WD system warning lights, service messages, or flashing indicators are displayed in the Instrument Panel Cluster \(IPC\). ● The vehicle does not engage 4WD properly. This bulletin involves reprogramming the DTCM with the latest available software.
- [S2621000004](/bulletins/11038329.md), 2026-10-07, Service bulletin: POWER TRAIN. The Customer May Complain About a Popping Noise, Grinding Noise, or an Intermittent No Reverse or Forward Transmission Engagement. The Tech May Find Damaged and/or Worn Transmission Output Shaft Splines \(850RE Transmission Only\)
- [9100900](/bulletins/11037346.md), 2026-09-17, Service bulletin: ELECTRICAL SYSTEM; STRUCTURE:BODY. Passive Entry O/S Dr Handle Prior to replacing an inoperative passive entry door handle, perform Star Online S2623000040.
- [16C Combo Rev3](/bulletins/11036183.md), 2026-08-13, Warranty extension: ELECTRICAL SYSTEM. EMISSION RECALL – NORTH AMERICA Check Engine/Malfunction Indicator Lamp 16C The instrument panel cluster on about 32,587 of the above vehicles may have an inoperable check engine/malfunction indicator lamp \(CEL/MIL\). \(JT\) vehicles: CEL/MIL and cargo lamp indicator function are swapped. \(JL\) vehicles: CEL/MIL will not turn on. The CEL/MIL in and of itself will not affect emissions. However, if there was an emission issue that would require illumination of the CEL/MIL, the customer would not be alerted. The vehicle would be non\-compliant to the OBD II regulation.
- [08\-298\-26 REV. A](/bulletins/11036150.md), 2026-08-13, Service bulletin: ELECTRICAL SYSTEM. Instrument Panel Cluster \(IPC\) Blank XZ1 Warranty Extension Customers may experience the following: SYMPTOM: ● \*\*A blank electronic vehicle information center \(EVIC\) in the IPC. No information is displayed for the fuel level, temperature gauge, odometer, outside temperature, PRNDL and optional digital speedometer Fig. 1. IMPORTANT\! The analog speedometer and tachometer gauges continue to function normally Fig. 1\*\*. This bulletin involves replacing the IPC.
- [113809](/bulletins/11035998.md), 2026-08-06, Warranty extension: ELECTRICAL SYSTEM. ID\-26\-37 \(XZ1\) Instrument Panel Cluster \(IPC\) \- Select 2018 \- 2020 Jeep Wrangler \(JL\) and 2020 Jeep Gladiator \(JT\)
- [113813](/bulletins/11035997.md), 2026-08-06, Warranty extension: ELECTRICAL SYSTEM. D\-26\-17 \(XZ1\) Instrument Panel Cluster \(IPC\) \- Select 2018 \- 2020 Jeep Wrangler \(JL\) and 2020 Jeep Gladiator \(JT\)
- [08\-298\-26](/bulletins/11035973.md), 2026-08-06, Service bulletin: ELECTRICAL SYSTEM. Instrument Panel Cluster \(IPC\) Blank XZ1 Warranty Extension Customers may experience the following: SYMPTOM: ● A blank IPC display. No information is displayed for the speedometer, fuel level, temperature gauge, odometer, outside temperature and PRNDL. NOTE: The speedometer and tachometer continue to function normally. This bulletin involves replacing the IPC.
- [112862](/bulletins/11034372.md), 2026-07-02, Service bulletin: ELECTRICAL SYSTEM. MOTOR \- BLOWER WITH WHEEL

JSON: [/v1/bulletins/10174232](/v1/bulletins/10174232)

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