TECHNICAL INFORMATION TIP

Reference Number(s): TOY0331AP, Date of Issue: April, 1998

KNOCK SENSOR DIES AFTER A HEAD GASKET REPLACEMENT

YEAR(S): 1988-95

MANUFACTURER: Toyota

MODEL(S): Trucks

DATE OF ISSUE: April, 1998

ISSUE & TIP

A head gasket replacement on V-6 Toyota trucks may be all it takes to kill the knock sensor. The CHECK ENGINE light may come on and a knock sensor code may be set when the engine is started for the first time after the repairs.

Be very careful during disassembly and repair, as the knock sensor wire can become very brittle internally. Moving the harness around during the engine disassembly/reassembly may cause an internal break that will not be visible on the outside of the wire insulation.

Separate wire harnesses are now available from Toyota dealers. We have also had some success in the past by making a new knock sensor wire from microphone cable. This cable is available at your local Radio Shack or similar electronics store.

Courtesy of Import Service Magazine with thanks to:

Keith Ullrich

Mark Motors

Wisconsin Rapids, Wisconsin

REFERENCE NUMBER

TOY0331AP

NOTE: This information has been obtained from sources generally believed to be reliable. Use your own judgment before relying on this data. Neither the suppliers of these Technical Information Tips, nor lemon-25 Repair Information Company, LLC, guarantees or assumes responsibility for data accuracy or completeness, nor is liability assumed by the suppliers of these Technical Information Tips or lemon-25 Repair Information Company, LLC, for any claims or damages resulting from the use of this information.

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.

Safety Warning

Knock Sensor Knockout (TOY0331AP)