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 DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - PINPOINT TESTS (EXCEPT DIESEL & HYBRID) (A TO H)PINPOINT TESTS DG: KNOCK SENSOR (KS)TEST PROCEDURE

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

Test Procedure

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

DG1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)

NOTE: The DTC P06B6 or P130D may be accompanied by other DTCs. Diagnose all other DTCs first.

Verify the KS is correctly installed before continuing diagnosis. Refer to the appropriate Electronic Engine Controls article.

Are DTCs P0325, P0327, P0328, P032A, P032C, P032D, P0330, P0332, P0333, P033A, P033C, P033D, P06B6 or P130D present?

Yes	No
For DTCs P06B6 or P130D, GO to DG6 For all others, GO to DG2	RETURN to Symptom Charts for further direction.

DG2 CHECK THE KS CIRCUIT FOR AN OPEN

Ignition OFF.
KS connector disconnected.
PCM connector disconnected.
For KS11,

Measure the resistance between:

(+) KS11 Connector, Harness Side	(-) PCM Connector, Harness Side
KS11	KS11
KS11RTN	KS11RTN

For KS12,

Measure the resistance between:

(+) KS12 Connector, Harness Side	(-) PCM Connector, Harness Side
KS12	KS12
KS12RTN	KS12RTN

For KS21,

Measure the resistance between:

(+) KS21 Connector, Harness Side	(-) PCM Connector, Harness Side
KS21	KS21
KS21RTN	KS21RTN

For KS22,

Measure the resistance between:

(+) KS22 Connector, Harness Side	(-) PCM Connector, Harness Side
KS22	KS22
KS22RTN	KS22RTN

Are the resistances less than 5 ohms?

Yes	No
GO to DG3	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

DG3 CHECK THE KS CIRCUIT FOR A SHORT TO GROUND

For KS11,

Measure the resistance between:

(+) KS11 Connector, Harness Side	(-)
KS11	Ground
KS11RTN	Ground

For KS12,

Measure the resistance between:

(+) KS12 Connector, Harness Side	(-)
KS12	Ground
KS12RTN	Ground

For KS21,

Measure the resistance between:

(+) KS21 Connector, Harness Side	(-)
KS21	Ground
KS21RTN	Ground

For KS22,

Measure the resistance between:

(+) KS22 Connector, Harness Side	(-)
KS22	Ground
KS22RTN	Ground

Are the resistances greater than 10K ohms?

Yes	No
GO to DG4	REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

DG4 CHECK THE KS CIRCUIT FOR A SHORT TO VOLTAGE

Ignition ON, engine OFF.
For KS11,

Measure the voltage between:

(+) KS11 Connector, Harness Side	(-)
KS11	Ground
KS11RTN	Ground

For KS12,

Measure the voltage between:

(+) KS12 Connector, Harness Side	(-)
KS12	Ground
KS12RTN	Ground

For KS21,

Measure the voltage between:

(+) KS21 Connector, Harness Side	(-)
KS21	Ground
KS21RTN	Ground

For KS22,

Measure the voltage between:

(+) KS22 Connector, Harness Side	(-)
KS22	Ground
KS22RTN	Ground

Is any voltage present?

Yes	No
REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.	GO to DG5

DG5 CHECK THE KS CIRCUIT FOR INTERMITTENT CONCERNS

Ignition OFF.
While observing the resistance, wiggle, shake, and bend small sections of the wiring harness working from the sensor to the PCM.
For KS11,

Measure the resistance between:

(+) KS11 Connector, Harness Side	(-) PCM Connector, Harness Side
KS11	KS11
KS11RTN	KS11RTN

For KS12,

Measure the resistance between:

(+) KS12 Connector, Harness Side	(-) PCM Connector, Harness Side
KS12	KS12
KS12RTN	KS12RTN

For KS21,

Measure the resistance between:

(+) KS21 Connector, Harness Side	(-) PCM Connector, Harness Side
KS21	KS21
KS21RTN	KS21RTN

For KS22,

Measure the resistance between:

(+) KS22 Connector, Harness Side	(-) PCM Connector, Harness Side
KS22	KS22
KS22RTN	KS22RTN

Are the resistances less than 5 ohms?

Yes	No
INSTALL a new KS. REFER to the appropriate Electronic Engine Controls article. Clear the PCM DTCs. REPEAT the self-test.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

DG6 IDENTIFY THE TYPE OF KNOCK

NOTE: Knock counts on a single cylinder may indicate a concern with the ignition or fuel components for the suspect cylinder. Knock counts distributed among multiple cylinders may indicate a fuel quality concern.

Ignition ON, engine running.
Access the PCM and monitor the KNK_CNTR_CYL1 (MODE), KNK_CNTR_CYL2 (MODE), KNK_CNTR_CYL3 (MODE), KNK_CNTR_CYL4 (MODE), KNK_CNTR_CYL5 (MODE) and KNK_CNTR_CYL6 (MODE) PIDs.

Are the majority of the knock counts on a single cylinder?

Yes	No
DIAGNOSE ignition coil and fuel injection components for the suspect cylinder. REPAIR or INSTALL a new component as necessary. Clear the PCM DTCs. REPEAT the self-test.	GO to DG7

DG7 CHECK THE LEARNED OCTANE ADJUSTMENT

Access the PCM and monitor the OCTADJ_R_LRND (PER) PID.

Does the OCTADJ_R_LRND PID read between -85% to -100%?

Yes	No
DRAIN and CLEAN the fuel system, REFILL with correct grade fuel. Clear the PCM DTCs. REPEAT the self-test.	INSTALL a new KS. REFER to the appropriate Electronic Engine Controls article. Clear the PCM DTCs. REPEAT the self-test.

RENDER: 1.0x

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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.