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Service bulletin 18-074-26 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.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id11038535
Published by NHTSA2026-10-16
Manufacturer's number18-074-26 REV. A
Manufacturer's date2026-10-10
NHTSA componentENGINE

NHTSA's summary

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P013E-00 - O2 Sensor Delayed Response - Rich to Lean Bank 1 Sensor 2. ● P014A-00 - O2 Sensor Delayed Response - Rich to Lean Bank 2 Sensor 2. ● B1811-00 - Driver Door Ajar Input Circuit Low. ● B25C7-00 -Driver Door Ajar Switch 2 Circuit Low.** ● P2AF6-00 - Starter Relay 3 Stuck Off (with DBSM). ● P014B-00 - O2 Sensor 2-2 Delayed Response-Lean To Rich. ● P062B-00 - Internal Control Module Fuel Injector Control Performance. Customers may also comment on the following: ● Electronic Start Stop (ESS) inoperative or "Auto Stop/Start Not Ready" message displayed in the Instrument Panel Cluster (IPC). NOTE: **Normal Auto Stop/Start inhibit conditions should not be considered the cause of this concern. The condition is associated with DTC P2AF6.** The following software enhancements are also available: ● **Improvements to prevent misfire DTCs P0300-P0306 that may set if one of the following DTCs set: ○ P0355-00 - Ignition Coil 5 Circuit. ○ P0336-00 - Crankshaft Position Sensor Performance.** ● Update to enable Exhaust Gas Recirculation (EGR) disable during gear shift for smoother shifting. ● Update for the Brake System Control Module (BSCM) MIL illumination request not setting the MIL on the Powertrain Control Module (PCM). This bulletin involves inspecting and possibly reprogramming the PCM with the latest available software.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine

Trouble codes named

B1811, B25C7, P013E, P014A, P014B, P0300, P0306, P0336, P0355, P062B, P2AF6

Vehicles listed
JEEP GRAND WAGONEER2026

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Other bulletins for the same vehicles and component
18-074-26 REV. A2026-10-16. Service bulletin. Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P013E-00 - O2 Sensor Delayed Response - Rich to Lean Bank 1 Sensor 2. ● P014A-00 - O2 Sensor Delayed Response - Rich to Lean Bank 2 Sensor 2. ● B1811-00 - Driver Door Ajar Input Circuit Low. ● B25C7-00 -Driver Door Ajar Switch 2 Circuit Low.** ● P2AF6-00 - Starter Relay 3 Stuck Off (with DBSM). ● P014B-00 - O2 Sensor 2-2 Delayed Response-Lean To Rich. ● P062B-00 - Internal Control Module Fuel Injector Control Performance. Customers may also comment on the following: ● Electronic Start Stop (ESS) inoperative or "Auto Stop/Start Not Ready" message displayed in the Instrument Panel Cluster (IPC). NOTE: **Normal Auto Stop/Start inhibit conditions should not be considered the cause of this concern. The condition is associated with DTC P2AF6.** The following software enhancements are also available: ● **Improvements to prevent misfire DTCs P0300-P0306 that may set if one of the following DTCs set: ○ P0355-00 - Ignition Coil 5 Circuit. ○ P0336-00 - Crankshaft Position Sensor Performance.** ● Update to enable Exhaust Gas Recirculation (EGR) disable during gear shift for smoother shifting. ● Update for the Brake System Control Module (BSCM) MIL illumination request not setting the MIL on the Powertrain Control Module (PCM). This bulletin involves inspecting and possibly reprogramming the PCM with the latest available software.
9100861 Rev 32026-08-06. Service bulletin. PUMP, Auxiliary Coolant Before replacing the Auxiliary Coolant Pump, please perform the following steps: 1) Key ON/OFF and let the after-run pump run for at least 20 minutes before moving on to step #2. 2) Inspect the pump connector area for presence of water. 3) Inspect the pump connector for corrosion. 4) Inspect the pump for coolant contamination as this can cause the pump to stall. 5) Inspect battery terminals for damage to rule out a battery drainage issue. 6) Ensure the PCM is up-to-date with the latest available flash. If correct repair is not performed then the claim or condition will be recovered by Warranty Operations.
18-074-262026-07-29. Service bulletin. Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P2AF6-00 - Starter Relay 3 Stuck Off (with DBSM). ● P014B-00 - O2 Sensor 2-2 Delayed Response-Lean To Rich. ● P062B-00 - Internal Control Module Fuel Injector Control Performance. Customers may also comment on the following: ● Engine Stop/Start (ESS) inoperative with "Auto Stop Start Not Ready" message in Instrument Panel Cluster (IPC). The following software enhancements are also available: ● Update to enable Exhaust Gas Recirculation (EGR) disable during gear shift for smoother shifting. ● Update for the Brake System Control Module (BSCM) MIL illumination request not setting the MIL on the Powertrain Control Module (PCM). This bulletin involves inspecting and possibly reprogramming the PCM with the latest available software.
9100861 Rev 12026-07-23. Service bulletin. PUMP, Auxiliary Coolant Before replacing the Auxiliary Coolant Pump, please perform the following steps: 1) Key ON/OFF and let the after-run pump run for at least 20 minutes before moving on to step #2. 2) Inspect the pump connector area for presence of water. 3) Inspect the pump connector for corrosion. 4) Inspect the pump for coolant contamination as this can cause the pump to stall. 5) Inspect battery terminals for damage to rule out a battery drainage issue. 6) Ensure the PCM is up-to-date with the latest available flash.
91008612026-07-18. Service bulletin. PUMP, Auxiliary Coolant Before replacing the Auxiliary Coolant Pump, please perform the following steps: 1) Key ON/OFF and let the after-run pump run for at least 20 minutes before moving on to step #2. 2) Inspect the pump connector area for presence of water. 3) Inspect the pump connector for corrosion. 4) Inspect the pump for coolant contamination as this can cause the pump to stall. 5) Ensure the PCM is up-to-date with the latest available flash. 6) Inspect battery terminals for damage to rule out a battery drainage issue.
09-012-26 REV. A2026-07-02. Service bulletin. Oil Pan Leak Customers may experience the following: SYMPTOM: ● 'Low Oil Level' message on in the Instrument Panel Cluster (IPC). ● Oil Leak. This bulletin involves replacing the engine oil pan.
09-012-262026-07-02. Service bulletin. Oil Pan Leak Customers may experience the following: SYMPTOM: ● 'Low Oil Level' message on in the Instrument Panel Cluster (IPC). ● Oil Leak. This bulletin involves replacing the engine oil pan.
91008322026-06-18. Service bulletin. Before replacing the starter, please follow the published diagnostics in the Service Information at 08 - Electrical / 8F - Engine Systems / Starting / Diagnosis and Testing / STANDARD STARTING SYSTEM. Updates to this procedure have been recently made and should be followed.
1120372026-05-20. Service bulletin. MODULE - IGNITION
91007902026-04-01. Service bulletin. Before replacing the water pump on 3.0L SO/HO, please follow the updated WATER PUMP INSPECTION diagnostic procedure to confirm the leak persists "09 - Engine, 3.0L GMET6 / Cooling System / Engine Cooling / Diagnosis and Testing / COOLING SYSTEM LEAKS"