Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSFORD2021TRANSIT-350 HD BASE, VAN CARGO EXTENDED, 3.5L ENG VIN 8, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 13 (ENGINE CONTROLS - PINPOINT TESTS (DIESEL))PINPOINT TESTS RH: REDUCTANT HEATERINTRODUCTION

2021 Ford Transit-350 HD Base, Van Cargo Extended, 3.5L Eng VIN 8, AWD

Pinpoint Tests RH: REDUCTANT Heater: Introduction

2021 Ford Transit-350 HD Base, Van Cargo Extended, 3.5L Eng VIN 8, AWDSECTION Introduction

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2018 Ford Transit-350 HD, 2018 Ford Transit-350, 2018 Ford Transit-250, 2018 Ford Transit-150, and 2018 Ford F-550 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Regeneration may occur during normal operation. During regeneration, diagnostic procedures may display biased values. If a regeneration occurs during diagnostic procedures, allow the process to complete before continuing diagnostics.

This pinpoint test is intended to diagnose the following:

reductant heaters
harness circuits: GND, RDHTRC1, RDHTRC2, RDHTRC3 and RDHTRPWR
glow plug control module (GPCM)
reductant dosage control module (5H298)

Fig 1: Battery Junction Box-B (BJB-B) Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
42	GND (Ground)

Fig 2: Battery Junction Box-C (BJB-C) Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
28	RDHTRCTRL (Reductant Heater Control)

Fig 3: Battery Junction Box-D (BJB-D) Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
50	RDHTRPWR (Reductant Heater Power)

Fig 4: Reductant Heater And Sender Assembly Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
2	GND (Ground)
1	RDHTRC1 (Reductant Heater Control 1)

Fig 5: Reductant Pump Assembly Connector

Courtesy of FORD MOTOR CO.

Vehicle	Connector	Pin	Circuit
Transit	A	2 1	RDHTRC2 GND
All other vehicles	B	11 9	GND RDHTRC1

Fig 6: Reductant Pressure Line Heater Assembly Connector

Courtesy of FORD MOTOR CO.

Vehicle	Connector	Pin	Circuit
Transit	A	1 2	RDHTRC3 GND
All other vehicles	A	2 1	GND RDHTRC2

Fig 7: Reductant Heater Relay Connector

Courtesy of FORD MOTOR CO.

Vehicle	Connector	Pin	Circuit
Transit	A	2 5 1 3	RDHTRCTRL RDHTRPWR GND B+
All other vehicles	A	1 5 2 3	RDHTRCTRL RDHTRPWR GND B+

Fig 8: Glow Plug Control Module-C (GPCM-C) Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
13	RDHTRC2 (Reductant Heater Control 2)
15	RDHTRC1 (Reductant Heater Control 1)
2	RDHTRCTRL (Reductant Heater Control)
16	RDHTRPWR (Reductant Heater Power)

Fig 9: Reductant Dosage Control Module Relay Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
5	VPWR (Vehicle Power)
1,	3 B+ (Battery Positive Voltage)

Fig 10: Reductant Dosage Control Module Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
6	RDHTRC3 (Reductant Heater Control 3)
2	RDHTRC2 (Reductant Heater Control 2)
4	RDHTRC1 (Reductant Heater Control 1)
29, 7	PWRGND (Power Ground)
1, 3, 5, 51, 73	VPWR (Vehicle Power)

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.