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Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.
DTC U0073, U1900, U2516 DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 DETERMINING LOCATION OF A MALFUNCTION  Yes Go to Step 13.
No Go to the next step.
2 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 11 (instrument panel harness) or steering angle sensor?
Yes Go to Step 24.
No Go to the next step.
3 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 10 (instrument panel harness)?
Yes Go to Step 30.
No Go to the next step.
4 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 9 (instrument panel harness) or TPMS control module?
Yes Go to Step 26.
No Go to the next step.
5 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 8 (instrument panel harness)?
Yes Go to Step 32.
No Go to the next step.
6 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 7 (rear harness) or keyless control module?
Yes Go to Step 28.
No Go to the next step.
7 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 6 (rear harness)?
Yes Go to Step 34.
No Go to the next step.
8 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 5 (front harness) or ABS (DSC) HU/CM?
Yes Go to Step 22.
No Go to the next step.
9 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 3 (front harness)?
Yes Go to Step 36.
No Go to the next step.
10 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 4 (front harness) or the TCM?
Yes Go to Step 38.
No Go to the next step.
11 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 2 (front harness) or EPS control module?
Yes Go to Step 40.
No Go to the next step.
12 DETERMINING LOCATION OF A MALFUNCTION 
  • Is malfunctioning part wiring harness 1 (front harness) or PCM?
Yes Go to Step 42.
No Troubleshooting completed.
13 INSPECT INSTRUMENT CLUSTER CONNECTOR 
  • Disconnect negative battery cable.
  • Disconnect instrument cluster connector.
  • Is instrument cluster connector normal?
Yes Go to the next step.
No Replace wiring harness.
14
  • Is inspected vehicle AT?
Yes Go to the next step.
No Go to Step 16.
15 INSPECT WIRING HARNESS BETWEEN TCM AND INSTRUMENT CLUSTER 
  • Disconnect TCM connector.
  • Inspect following wiring harness between TCM and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • 1Y-1L (CAN_L)
    • 1V-1J (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
16 INSPECT WIRING HARNESS BETWEEN ABS (DSC) HU/CM AND INSTRUMENT CLUSTER 
  • Disconnect ABS (DSC) HU/CM connector.
  • Inspect following wiring harness between ABS (DSC) HU/CM and instrument cluster terminals for short to ground, short power supply, and open circuit:

    ABS 

    • R-1L (CAN_L)
    • O-1J (CAN_H)

    DSC 

    • I-1L (CAN_L)
    • H-1J (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
17 INSPECT WIRING HARNESS BETWEEN PCM AND INSTRUMENT CLUSTER 
  • Disconnect PCM connector.
  • Inspect following wiring harness between PCM and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • 4S-1L (CAN_L)
    • 4V-1J (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
18 INSPECT WIRING HARNESS BETWEEN STEERING ANGLE SENSOR AND INSTRUMENT CLUSTER 
  • Disconnect steering angle sensor connector.
  • Inspect following wiring harness between steering angle sensor and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • -F-1L (CAN_L)
    • -E-1J (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
19 INSPECT WIRING HARNESS BETWEEN TPMS CONTROL MODULE AND INSTRUMENT CLUSTER 
  • Disconnect TPMS control module connector.
  • Inspect following wiring harness between TPMS control module and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • -G-1L (CAN_L)
    • -E-1J (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
20 INSPECT WIRING HARNESS BETWEEN EPS CONTROL MODULE AND INSTRUMENT CLUSTER 
  • Disconnect EPS control module connector.
  • Inspect following wiring harness between EPS control module and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • 2K-1L (CAN_L)
    • 2M-1J (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
21 INSPECT WIRING HARNESS BETWEEN KEYLESS CONTROL MODULE AND INSTRUMENT CLUSTER 
  • Disconnect keyless control module connector.
  • Inspect following wiring harness between keyless control module and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • 3B-1L (CAN_L)
    • 3A-1J (CAN_H)
  • Is wiring harness normal?
Yes Replace instrument cluster, then go to Step 44.
No Replace wiring harness.
22 INSPECT ABS (DSC) HU/CM CONNECTOR 
  • Disconnect negative battery cable.
  • Disconnect ABS (DSC) HU/CM connector.
  • Is ABS (DSC) HU/CM connector normal?
Yes Go to the next step.
No Replace wiring harness.
23 INSPECT WIRING HARNESS BETWEEN ABS (DSC) HU/CM AND INSTRUMENT CLUSTER 
  • Disconnect instrument cluster connector.
  • Inspect following wiring harness between ABS (DSC) HU/CM and instrument cluster terminals for short to ground, short power supply, and open circuit:

    ABS 

    • -R-1L (CAN_L)
    • -O-1J (CAN_H)

    DSC 

    • -I-1L (CAN_L)
    • -H-1J (CAN_H)
  • Is wiring harness normal?
Yes Replace ABS HU/CM (DSC HU/CM), then go to Step 44.
No Replace wiring harness.
24 INSPECT STEERING ANGLE SENSOR CONNECTOR 
  • Disconnect negative battery cable.
  • Disconnect steering angle sensor connector.
  • Is steering angle sensor connector normal?
Yes Go to the next step.
No Replace wiring harness.
25 INSPECT WIRING HARNESS BETWEEN STEERING ANGLE SENSOR AND INSTRUMENT CLUSTER 
  • Disconnect instrument cluster connector.
  • Inspect following wiring harness between steering angle sensor and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • -F-1L (CAN_L)
    • -E-1J (CAN_H)
  • Is wiring harness normal?
Yes Replace steering angle sensor, then go to Step 44.
No Replace wiring harness.
26 INSPECT TPMS CONTROL MODULE CONNECTOR 
  • Disconnect negative battery cable.
  • Disconnect TPMS control module connector.
  • Is TPMS control module connector normal?
Yes Go to the next step.
No Replace wiring harness.
27 INSPECT WIRING HARNESS BETWEEN TPMS CONTROL MODULE AND INSTRUMENT CLUSTER 
  • Disconnect instrument cluster connector.
  • Inspect following wiring harness between TPMS control module and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • -G-1L (CAN_L)
    • -E-1J (CAN_H)
  • Is wiring harness normal?
Yes Replace TPMS control module, then go to Step 44.
No Replace wiring harness.
28 INSPECT KEYLESS CONTROL MODULE CONNECTOR 
  • Disconnect negative battery cable.
  • Disconnect keyless control module connector.
  • Is keyless control module connector normal?
Yes Go to the next step.
No Replace wiring harness.
29 INSPECT WIRING HARNESS BETWEEN KEYLESS CONTROL MODULE AND INSTRUMENT CLUSTER 
  • Disconnect instrument cluster connector.
  • Inspect following wiring harness between keyless control module and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • 3B-1L (CAN_L)
    • 3A-1J (CAN_H)
  • Is wiring harness normal?
Yes Replace keyless control module, then go to Step 44.
No Replace wiring harness.
30 INSPECT WIRING HARNESS BETWEEN TPMS CONTROL MODULE AND STEERING ANGLE SENSOR 
  • Disconnect negative battery cable.
  • Disconnect TPMS control module connector.
  • Disconnect steering angle sensor connector.
  • Inspect following wiring harness between TPMS control module and steering angle sensor terminals for short to ground, short power supply, and open circuit:
    • -G-F (CAN_L)
    • -E-E (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
31 INSPECT WIRING HARNESS BETWEEN TPMS CONTROL MODULE AND INSTRUMENT CLUSTER 
  • Disconnect negative battery cable.
  • Disconnect TPMS control module connector.
  • Disconnect instrument cluster connector.
  • Inspect following wiring harness between TPMS control module and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • -G-1L (CAN_L)
    • -E-1J (CAN_H)
  • Is wiring harness normal?
Yes Go to Step 44.
No Replace wiring harness.
32 INSPECT WIRING HARNESS BETWEEN TPMS CONTROL MODULE AND KEYLESS CONTROL MODULE 
  • Disconnect negative battery cable.
  • Disconnect TPMS control module connector.
  • Disconnect keyless control module connector.
  • Inspect following wiring harness between TPMS control module and keyless control module terminals for short to ground, short power supply, and open circuit:
    • -G-3B (CAN_L)
    • -E-3A (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
33 INSPECT WIRING HARNESS BETWEEN KEYLESS CONTROL MODULE AND INSTRUMENT CLUSTER 
  • Disconnect negative battery cable.
  • Disconnect keyless control module connector.
  • Disconnect instrument cluster connector.
  • Inspect following wiring harness between keyless control module and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • 3B-1L (CAN_L)
    • 3A-1J (CAN_H)
  • Is wiring harness normal?
Yes Go to Step 44.
No Replace wiring harness.
34 INSPECT WIRING HARNESS BETWEEN ABS (DSC) HU/CM AND KEYLESS CONTROL MODULE 
  • Disconnect negative battery cable.
  • Disconnect ABS (DSC) HU/CM connector.
  • Disconnect keyless control module connector.
  • Inspect following wiring harness between ABS (DSC) HU/CM and keyless control module terminals for short to ground, short power supply, and open circuit:

    ABS 

    • -R-3B (CAN_L)
    • -O-3A (CAN_H)

    DSC 

    • -I-3B (CAN_L)
    • -H-3A (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
35 INSPECT WIRING HARNESS BETWEEN ABS (DSC) HU/CM AND INSTRUMENT CLUSTER 
  • Disconnect negative battery cable.
  • Disconnect ABS (DSC) HU/CM connector.
  • Disconnect instrument cluster connector.
  • Inspect following wiring harness between ABS (DSC) HU/CM and instrument cluster terminals for short to ground, short power supply, and open circuit:

    ABS 

    • -R-1L (CAN_L)
    • -O-1J (CAN_H)

    DSC 

    • 1-1L (CAN_L)
    • -H-1J (CAN_H)
  • Is wiring harness normal?
Yes Go to Step 44.
No Replace wiring harness.
36 INSPECT WIRING HARNESS BETWEEN EPS CONTROL MODULE AND ABS (DSC) HU/CM 
  • Disconnect negative battery cable.
  • Disconnect EPS control module connector.
  • Disconnect ABS (DSC) HU/CM connector.
  • Inspect following wiring harness between EPS control module and ABS (DSC) HU/CM terminals for short to ground, short power supply, and open circuit:

    ABS 

    • 2K-R (CAN_L)
    • 2M-O (CAN_H)

    DSC 

    • 2K-I (CAN_L)
    • 2M-H (CAN_H)
  • Is wiring harness normal?
Yes Go to the next step
No Replace wiring harness.
37 INSPECT WIRING HARNESS BETWEEN PCM AND ABS (DSC) HU/CM 
  • Disconnect negative battery cable.
  • Disconnect PCM connector.
  • Disconnect ABS (DSC) HU/CM connector.
  • Inspect following wiring harness between PCM and ABS (DSC) HU/CM terminals for short to ground, short power supply, and open circuit:

    ABS 

    • 4S-R (CAN_L)
    • 4V-O (CAN_H)

    DSC 

    • 4S-I (CAN_L)
    • 4V-H (CAN_H)
  • Is wiring harness normal?
Yes Go to Step 44.
No Replace wiring harness.
38 INSPECT TCM CONNECTOR 
  • Disconnect negative battery cable.
  • Disconnect TCM connector.
  • Is TCM connector normal?
Yes Go to the next step.
No Replace wiring harness.
39 INSPECT WIRING HARNESS BETWEEN TCM AND INSTRUMENT CLUSTER 
  • Disconnect instrument cluster connector.
  • Inspect following wiring harness between TCM and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • 1Y-1L (CAN_L)
    • 1V-1J (CAN_H)
  • Is wiring harness normal?
Yes Replace TCM, then go to Step 44.
No Replace wiring harness.
40 INSPECT EPS CONTROL MODULE CONNECTOR 
  • Disconnect negative battery cable.
  • Disconnect EPS control module connector.
  • Is EPS control module connector normal?
Yes Go to the next step.
No Replace wiring harness.
41 INSPECT WIRING HARNESS BETWEEN EPS CONTROL MODULE AND INSTRUMENT CLUSTER 
  • Disconnect instrument cluster connector.
  • Inspect following wiring harness between EPS control module and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • 2K-1L (CAN_L)
    • 2M-1J (CAN_H)
  • Is wiring harness normal?
Yes Replace EPS control module, then go to Step 44.
No Replace wiring harness.
42 INSPECT PCM CONNECTOR 
  • Disconnect negative battery cable.
  • Disconnect PCM connector.
  • Is PCM connector normal?
Yes Go to the next step.
No Replace wiring harness.
43 INSPECT WIRING HARNESS BETWEEN PCM AND INSTRUMENT CLUSTER 
  • Disconnect PCM connector.
  • Inspect following wiring harness between PCM and instrument cluster terminals for short to ground, short power supply, and open circuit:
    • 4S-1L (CAN_L)
    • 4V-1J (CAN_H)
  • Is wiring harness normal?
Yes Replace PCM, then go to the next step.
No Replace wiring harness.
44 CHECK DTC INDICATE 
  • Connect PCM connector.
  • Connect EPS control module connector.
  • Connect TCM connector.
  • Connect ABS (DSC) HU/CM connector.
  • Connect keyless control module connector.
  • Connect TPMS control module connector.
  • Connect steering angle sensor connector.
  • Connect instrument cluster connector.
  • Clear DTC from module memory using SST  (WDS or equivalent).
  • Perform KOEO/KOER self-test.
  • Are DTCs U0073, U1900 and/or U2516 indicated?
Yes Repeat from Step 1.
No Troubleshooting completed.