Coolant Pump System Check 1998
Coolant Pump Diagnosis
The coolant pump is controlled by the HTCM. The HTCM sends a speed command to the coolant pump buffer which controls the coolant pump speed by pulse width modulating (percent duty cycle) the power to the pump. The coolant pump should operate any time the key is ON or the charge paddle is inserted into the charge receptacle. The coolant pump will operate at a faster speed whenever the A/C mode or the Heat Pump mode is selected.
Failure Modes
The coolant pump will not operate under the following conditions:
| • | The pump motor fails. |
| • | The coolant pump buffer fails. |
| • | The HTCM fails. |
| • | Power or ground is lost to the buffer. |
| • | One or more of the wires between the components opens or shorts to ground. |
| • | Communication is lost between the HTCM and the BPCM. |
Failure Action
If the coolant pump fails, charging and propulsion may be disabled if the temperature of the following components rises too high:
| • | The power inverter module (PIM) |
| • | The drive motor |
| • | The coolant |
| • | The charge receptacle |
Related DTCs
| • | HTCM DTC 014 |
| • | HTCM DTC 047 |
| • | HTCM DTC 050 |
| • | HTCM DTC 052 |
Telltale Illuminated
None
Other Control Interfaces
| • | The battery pack control module (BPCM) |
| • | The drive motor control module (DMCM) |
Diagnostic Aids
| • | Inspect the tightness of the female terminal grip with a spare male terminal. |
| • | If the problem is intermittent, wiggle the wire harness while observing a scan tool. Inspect for a value change or for the DTC to set. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the HVAC System Check? | -- | Go to Step 2 | Go to HVAC System Check |
2 |
Does the coolant pump operate? | -- | Go to Diagnostic Aids | Go to Step 3 |
3 |
Is an open or high resistance condition present? | -- | Go to Step 4 | Go to Step 5 |
4 | Repair the open or high resistance condition in CKT 250 (BLK) between the coolant pump buffer connector pin D and ground. Is the repair complete? | -- | Go to Step 18 | -- |
5 | Test for voltage at pin A of the coolant pump buffer connector. Is the voltage greater than the specified value? | 10 V | Go to Step 7 | Go to Step 6 |
6 | Locate and repair the loss of voltage on CKT 840 (ORN) between the coolant pump buffer and the fuse block. Is the repair complete? | -- | Go to Step 18 | -- |
7 | Test for voltage at pin C of the coolant pump buffer connector. Is the voltage greater than the specified value? | 10 V | Go to Step 9 | Go to Step 8 |
8 | Locate and repair the loss of voltage on CKT 5620 (ORN) between power distribution and the coolant pump buffer. Is the repair complete? | -- | Go to Step 18 | -- |
9 | Test for voltage at pin B of the coolant pump buffer connector. Is the voltage greater than the specified value? | 1.0 V | Go to Step 13 | Go to Step 10 |
10 | Test for voltage at the C2 connector of the HTCM by backprobing pin C11. Is the voltage greater than the specified value? | 1.0 V | Go to Step 11 | Go to Step 12 |
11 | Locate and repair the open in CKT 2014 (PNK) between the HTCM and the coolant pump buffer. Is the repair complete? | -- | Go to Step 18 | -- |
12 |
Is the repair complete? | -- | Go to Step 18 | -- |
13 |
Does either cavity indicate voltage greater than the specified value? | 10 V | Go to Step 15 | Go to Step 14 |
14 | Replace the coolant pump buffer. Is the repair complete? | -- | Go to Step 18 | -- |
15 | Connect a J 39200 DMM between both cavities at the coolant pump connector. Is the voltage greater than the specified value? | 10 V | Go to Step 16 | Go to Step 17 |
16 | Replace the coolant pump. Is the repair complete? | -- | Go to Step 18 | -- |
17 | Replace the coolant pump buffer. Is the repair complete? | -- | Go to Step 18 | -- |
18 |
Is the action complete? | -- | Go to HVAC System Check | -- |
