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How to Troubleshoot the Active Control Engine Mount (ACM) System
Intermittent Failures
The term intermittent failure means a system may have had a failure, but it checks OK now. Check for poor connections or loose terminals at all connectors related to the circuit that you are troubleshooting.
Opens and Shorts
Open and short are common electrical terms. An open is a break in a wire or at a connection. A short is an accidental connection of a wire to ground or to another wire. In simple electronics, this usually means something won't work at all. With complex electronics (such as PCMs) this can sometimes mean something works, but not the way it's supposed to.
How to Use the HDS
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Connect the HDS to the DLC (A) located under the driver's side of the dashboard. |
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Press the engine start/stop button to select the ON mode. |
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Check the DTC and note it. Also check the freeze data and/or the on-board snapshot data, and download any data found. Then refer to the indicated DTC's troubleshooting, and begin the appropriate troubleshooting procedure.
NOTE:
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Freeze data indicates the engine conditions when the first malfunction, was detected. |
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The HDS can read the DTC, freeze data, on-board snapshot, and current data about the active control engine mount (ACM) system. |
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For specific operations, refer to the user's manual that came with the HDS. | |
HDS Clear Command
The PCM stores DTCs about the ACM system even if there is no electrical power such as when the battery negative terminal or the No. A12-3 IG MAIN 1 (30 A) fuse is disconnected. Stored data based on failed parts should be cleared by using the CLEAR COMMAND of the HDS, if parts are replaced.
The HDS has two kinds of clear commands to meet this purpose. They are DTC clear, and PCM reset. The DTC clear command erases all stored DTC codes, freeze data, on-board snapshot, and readiness codes. This must be done with the HDS after reproducing the DTC during troubleshooting.
The PCM reset command erases all stored DTC codes, freeze data, on-board snapshot, readiness codes, and all specific data about the ACM system.
DTC Clear
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Clear the DTC with the HDS while the engine is stopped. |
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Press the engine start/stop button to select the OFF mode. |
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Press the engine start/stop button to select the ON mode, and wait 30 seconds. |
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Press the engine start/stop button to select the OFF mode, and disconnect the HDS from the DLC. |
ACM Reset
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Reset the PCM with the HDS while the engine is stopped. |
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Press the engine start/stop button to select the OFF mode. |
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Press the engine start/stop button to select the ON mode, and wait 30 seconds. |
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Press the engine start/stop button to select the OFF mode, and disconnect the HDS from the DLC. |
How to Troubleshoot Circuits at the Engine Mount Control Unit
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Connect one side of the patch cords terminals (A), to a commercially available digital multimeter (B), and connect the other side of the terminals (C) to a commercially available banana jack (Pomona Electronics Tool No. 3563 or equivalent) (D). |
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Using the wire insulation as a guide for the contoured tip of the backprobe adapter, gently slide the tip into the connector from the wire side until it touches the end of the wire terminal. |
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If you cannot get to the wire side of the connector or the wire side is sealed (A), disconnect the connector, and probe the terminals (B) from the terminal side. Do not force the probe into the connector.
Do not puncture the insulation on a wire. Punctures can cause poor or intermittent electrical connections. |
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