P1687 is a manufacturer-specific diagnostic trouble code, meaning its exact definition depends entirely on the vehicle make.
On some applications, it indicates a communication network failure, while on others, it points to a specific circuit malfunction.
Because the code definition varies, the exact application must be verified before testing any components. The code alone does not prove that a specific module has failed.
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Key Takeaways
- P1687 is a manufacturer-specific code, and its definition varies significantly by vehicle make and model.
- On certain Chrysler, Dodge, and Jeep applications, it indicates a loss of communication with the mechanical instrument cluster.
- On specific Mazda RX-8 applications, it points to a metering oil pump control circuit problem on the high flow side.
- On some GM and Acura applications, it may indicate a fuel injector driver fault or an automatic transmission signal issue.
- Diagnosis requires verifying the exact factory definition for your vehicle before testing any circuits or replacing modules.
P1687 Code Description and Implications
P1687 is a manufacturer-specific powertrain code, and its exact definition depends on the vehicle application.
Certain Chrysler, Dodge, and Jeep applications: P1687 indicates “No Cluster Bus Message” or “No MIC Bus Message.”
The powertrain control module detects that it is not receiving expected data messages from the mechanical instrument cluster over the vehicle communication network.
Specific Mazda RX-8 applications: P1687 signifies a “Metering oil pump control circuit high flow side problem.”
The powertrain control module detects an electrical fault in the circuit controlling the rotary engine’s metering oil pump.
Some GM and Acura applications: P1687 may indicate a fuel injector control module driver fault or an automatic transmission fuel injection signal circuit issue.
Common Causes of the P1687 Code
Because the code definition varies, the causes depend entirely on the verified system.
For Chrysler, Dodge, and Jeep communication applications, a faulty instrument cluster or an internal cluster failure is one possible cause.
Damaged wiring, corroded connectors, or poor grounds in the communication bus circuit can also disrupt data transmission.
For Mazda RX-8 metering oil pump applications, a failed metering oil pump motor or a faulty pump switch is a possible cause.
Wiring harness damage, vacuum leaks affecting the pump, or poor electrical connections at the pump connector can also trigger this code.
For other applications, causes may include a faulty control module, damaged injector wiring, or internal module driver failure.
Symptoms Associated With P1687
Symptoms vary widely based on the affected system and the exact vehicle application.
On Chrysler, Dodge, and Jeep applications, the primary symptom is an inoperative instrument cluster or gauges that read zero.
The dashboard may display a “No Bus” message, and the check engine light will illuminate.
On Mazda RX-8 applications, symptoms may include limp mode activation, reduced engine performance, or excessive oil consumption if the pump fails.
On other applications, symptoms may include engine misfires, rough idling, or transmission shifting issues depending on the exact circuit monitored.
Diagnosing the P1687 Trouble Code
Diagnosis must begin by confirming the exact factory definition for your specific make, model, and engine.
For Chrysler, Dodge, and Jeep applications, technicians use a scan tool to check for communication with the instrument cluster.
They also inspect the communication bus wiring for opens or shorts to ground or voltage.
For Mazda RX-8 applications, diagnosis involves checking the metering oil pump switch operation and verifying the pump motor coil resistance.
For other applications, targeted electrical testing of the specific signal or driver circuit is required according to manufacturer service information.
Repairing the P1687 Issue
Repairs must follow confirmed diagnosis and vary significantly by implementation.
If testing confirms an internal instrument cluster failure on a Chrysler, Dodge, or Jeep application, the cluster may require replacement or professional rebuilding.
Wiring repairs must be completed if harness damage or corrosion is found in the communication bus circuit.
If the metering oil pump or its switch fails testing on a Mazda RX-8, replacing the confirmed failed component is necessary.
Vacuum lines and oil supply lines to the metering pump should also be inspected and repaired if damaged.
Always verify the repair by clearing the codes and performing a test drive or key cycle.
Cost Considerations for P1687 Repairs
Repair costs depend heavily on the underlying fault and the specific vehicle application.
Addressing a wiring issue or a poor connection is less expensive, primarily involving diagnostic time and minor materials.
Replacing a metering oil pump or switch on a rotary engine involves moderate parts and labor costs.
Conversely, replacing or professionally rebuilding a modern instrument cluster can be a more significant investment.
Costs will also vary based on diagnostic time, component accessibility, and local labor rates.
Prevention Strategies for Future Occurrences
Prevention strategies are tied to the specific failure mechanism of the affected system.
For communication bus issues, keeping interior moisture levels low and avoiding damage to under-dash wiring harnesses can help prevent corrosion.
For Mazda RX-8 applications, maintaining the correct engine oil level and ensuring the metering oil pump system is free of vacuum leaks helps protect rotary components.
Some electrical or internal module failures occur without warning and cannot be reliably prevented through routine maintenance.
Troubleshooting Tips and Best Practices
Always verify the exact manufacturer definition for this error code before purchasing parts or beginning repairs.
Do not assume an instrument cluster has failed solely based on the code without targeted network and circuit testing.
When diagnosing communication networks, avoid bypassing modules or splicing into data lines, as this can disrupt the vehicle communication architecture.
Consult the exact manufacturer service information for your specific vehicle to ensure accurate diagnostic routines and specifications.
More OBD-II Codes
| P1686 | P1685 | P1684 | P1683 |
| P1682 | P1681 | P1688 | P1689 |
| P1690 | P1691 | P1692 | P1693 |
| P1694 | P1695 | P1680 | P1679 |
| P1678 | P1677 | P1676 | P1675 |
| P1674 | P1673 | P1672 | P1671 |
Frequently Asked Questions
Is P1687 a generic OBD-II code?
No. P1687 is a manufacturer-specific code, meaning its exact definition depends entirely on the vehicle make. It can indicate a communication network failure, a metering oil pump fault, or a specific circuit issue.
Can a P1687 code cause my gauges to stop working?
Yes, on certain Chrysler, Dodge, and Jeep applications, P1687 indicates a loss of communication with the instrument cluster. This can cause the gauges to read zero or the dashboard to display a “No Bus” message.
Will disconnecting the battery clear a P1687 code?
Disconnecting the battery may temporarily clear the code, but it does not repair the underlying electrical or communication fault. The code will likely return, and battery disconnection can erase valuable diagnostic data.
Does P1687 always mean the instrument cluster is bad?
No. While it indicates a communication failure on some applications, wiring faults, corroded connectors, or poor grounds can trigger the code. The cluster should only be replaced after targeted network testing confirms internal failure.
Can I drive my vehicle with a P1687 code?
Driving advice depends on the application. If the instrument cluster is dead, you may lack critical speedometer or temperature information, creating unsafe driving conditions. On rotary applications, a failed metering oil pump can cause severe engine damage.
What Should You Do About the P1687 Code?
Confirm the exact factory definition for your specific vehicle before attempting any repairs.
Because P1687 is manufacturer-specific, testing the wrong system will waste time and money.
Follow the applicable manufacturer diagnostic procedure to inspect the relevant system and components, then repair or replace the confirmed failed part.
